<PAGE>   1
                                                                     EXHIBIT 4.3

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933. SUCH SECURITIES AND ANY SECURITIES OR SHARES ISSUED HEREUNDER MAY
NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION
THEREFROM UNDER SAID ACT. COPIES OF THE AGREEMENT COVERING THE ISSUANCE OF THESE
SECURITIES MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY THE HOLDER OF
RECORD HEREOF TO THE SECRETARY OF THE COMPANY AT ITS PRINCIPAL EXECUTIVE
OFFICES.



                        WARRANT TO PURCHASE COMMON STOCK

                                       OF

                               CRITICAL PATH, INC.


        This certifies that, for value received, Vectis Group, LLC or its
registered assigns ("Holder") is entitled, subject to the terms and conditions
set forth below, to purchase from Critical Path, Inc. (the "Company"), in whole
or in part 500,000 fully paid and nonassessable shares (the "Warrant Shares") of
Common Stock of the Company (the "Common Stock") at a purchase price of $2.00
per share (as adjusted from time to time hereunder, the "Exercise Price"). The
number, character and Exercise Price of such shares of Common Stock are subject
to adjustment as provided below and all references to "Warrant Shares" and
"Exercise Price" herein shall be deemed to include any such adjustment or series
of adjustments. The term "Warrant" as used herein shall mean this Warrant, and
any warrants delivered in substitution or exchange therefor as provided herein.

        1. Term of Warrant. Subject to the terms and conditions set forth
herein, this Warrant shall be exercisable, in whole or in part, at any time and
from time to time during the term commencing on the date hereof and ending at
5:00 p.m., Pacific daylight savings time, on March 29, 2004, and shall be void
thereafter (the "Exercise Period").

        2. Exercise of Warrant.

        (a) Cash Exercise. This Warrant may be exercised by the Holder by (i)
the surrender of this Warrant to the Company, with the Notice of Exercise
annexed hereto duly completed and executed on behalf of the Holder, at the
office of the Company (or such other office or agency of the Company as it may
designate by notice in writing to the Holder at the address of the Holder
appearing on the books of the Company) during the Exercise Period and (ii) the
delivery of payment to the Company, for the account of the Company, by cash,
wire transfer of immediately available funds to a bank account specified by the
Company, or by certified or bank cashier's check, of the Exercise Price for the
number of Warrant Shares specified in the Exercise Form in lawful money of the
United States of America. The Company agrees that such Warrant Shares shall be
deemed to be issued to the Holder as the record holder of such Warrant Shares as
of the close of business on the date on which this Warrant shall have been
surrendered and payment made for the Warrant Shares as aforesaid. A stock
certificate or certificates for the Warrant


                                      -1-


<PAGE>   2
Shares specified in the Exercise Form shall be delivered to the Holder as
promptly as practicable, and in any event within twenty (20) days, thereafter.
If this Warrant shall have been exercised only in part, the Company shall, at
the time of delivery of the stock certificate or certificates, deliver to the
Holder a new Warrant evidencing the rights to purchase the remaining Warrant
Shares, which new Warrant shall in all other respects be identical with this
Warrant. No adjustments shall be made on Warrant Shares issuable on the exercise
of this Warrant for any cash dividends paid or payable to holders of record of
Common Stock prior to the date as of which the Holder shall be deemed to be the
record holder of such Warrant Shares.

        (b) Net Issue Exercise. In lieu of exercising this Warrant pursuant to
Section 2(a), this Warrant may be exercised by the Holder by the surrender of
this Warrant to the Company, with a duly executed Exercise Form marked to
reflect net issue exercise and specifying the number of shares of Common Stock
to be purchased, during normal business hours on any business day during the
Exercise Period. The Company agrees that such shares of Common Stock shall be
deemed to be issued to the Holder as the record holder of such shares of Common
Stock as of the close of business on the date on which this Warrant shall have
been surrendered as aforesaid. Upon such exercise, the Holder shall be entitled
to receive shares equal to the value of this Warrant (or the portion thereof
being canceled) by surrender of this Warrant to the Company together with notice
of such election in which event the Company shall issue to Holder a number of
shares of Common Stock computed as of the date of surrender of this Warrant to
the Company using the following formula:

               X = Y(A-B)
                   ------
                      A

Where      X =  the number of shares of Common Stock to be issued to Holder
                under this Section 2(b);

           Y =  the number of shares of Common Stock otherwise purchasable under
                this Warrant (as adjusted to the date of such calculation);

           A =  the Fair Market Value (as defined below) of one share of the
                Common Stock at the date of such calculation;

           B =  the Exercise Price (as adjusted to the date of such
                calculation).

        (c) Fair Market Value. For purposes of Section 2(b), the "Fair Market
Value" of one share of Common Stock shall mean, as of any date, the average of
the closing prices of the Common Stock's sales on all domestic securities
exchanges on which the Common Stock may at the time be listed, or, if there have
been no sales on any such exchange on any day, the average of the highest bid
and lowest asked prices for the Company's Common Stock on all such exchanges at
the end of such day, or, if on any day the Common Stock is not so listed, the
average of the representative bid and asked prices quoted in the NASDAQ System
as of 4:00 P.M., New York time, on such day, or, if on any day the Common Stock
is not quoted in the NASDAQ System, the average of the highest bid and lowest
asked prices for the Company's Common Stock on such day in the domestic
over-the-counter market as reported by the National Quotation Bureau,
Incorporated, or any similar successor organization, in each such case


                                      -2-


<PAGE>   3
averaged over a period of eleven (11) days consisting of the day as of which
"Fair Market Value" is being determined and the ten (10) consecutive business
days prior to such day; provided that if the Common Stock is listed on any
domestic securities exchange the term "business days" as used in this sentence
means business days on which such exchange is open for trading. If at any time
the Common Stock is not listed on any domestic securities exchange or quoted in
the NASDAQ System or the domestic over-the-counter market, the "Fair Market
Value" shall be the Fair Market Value thereof determined jointly by the Company
and the Holders of this Warrant representing a majority of the Common Stock
purchasable upon exercise this Warrant; provided that if such parties are unable
to reach agreement within a reasonable period of time, such fair value shall be
determined by an appraiser jointly selected by the Company and the Holders of
this Warrant representing a majority of the Common Stock purchasable upon
exercise of this Warrant. The determination of such appraiser shall be final and
binding on the Company and the Holders of this Warrant, and the fees and
expenses of such appraiser shall be paid by the Company.

        (d) This Warrant shall be deemed to have been exercised immediately
prior to the close of business on the date of its surrender for exercise as
provided above, and the person entitled to receive the shares of Common Stock
issuable upon such exercise shall be treated for all purposes as the holder of
record of such shares as of the close of business on such date. As promptly as
practicable on or after such date and in any event within ten (10) days
thereafter, the Company at its expense shall issue and deliver to the person or
persons entitled to receive the same a certificate or certificates for the
number of shares issuable upon such exercise. In the event that this Warrant is
exercised in part, the Company at its expense will execute and deliver a new
Warrant of like tenor exercisable for the number of shares for which this
Warrant may then be exercised.

        (e) The Company shall from time to time take all such action as may be
necessary to ensure that the par value per share of the unissued Warrant Shares
acquirable upon exercise of this Warrant is at all times equal to or less than
the Exercise Price then in effect. In the event that the Company fails to comply
with its obligations set forth in the foregoing sentence, the Purchaser may (but
shall not be obligated to) purchase Warrant Shares hereunder at par value, and
the Company shall be obligated to reimburse the Purchaser for the aggregate
amount of consideration paid in connection with such exercise in excess of the
Exercise Price then in effect.

        3. No Fractional Shares or Scrip. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. In lieu of any fractional share to which the Holder would otherwise be
entitled, the Company shall make a cash payment equal to the Exercise Price
multiplied by such fraction.

        4. Replacement of Warrant. On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of an
indemnity agreement reasonably satisfactory in form and substance to the Company
or, in the case of mutilation, on surrender and cancellation of this Warrant,
the Company at its expense shall execute and deliver, in lieu of this Warrant, a
new warrant of like tenor and amount.


                                      -3-


<PAGE>   4
        5. Rights of Stockholders; Limitation of Liability. Subject to Sections
8 and 10 of this Warrant, the Holder shall not be entitled to vote or receive
dividends or be deemed the holder of Common Stock or any other securities of the
Company that may at any time be issuable on the exercise hereof for any purpose,
nor shall anything contained herein be construed to confer upon the Holder, as
such, any of the rights of a stockholder of the Company or any right to vote for
the election of directors or upon any matter submitted to stockholders at any
meeting thereof, or to give or withhold consent to any corporate action (whether
upon any recapitalization, issuance of stock, reclassification of stock, change
of par value, or change of stock to no par value, consolidation, merger,
conveyance, or otherwise) or to receive notice of meetings, or to receive
dividends or subscription rights or otherwise until the Warrant shall have been
exercised as provided herein. No provision hereof, in the absence of affirmative
action by the Holder to purchase Warrant Shares, and no enumeration herein of
the rights or privileges of the Holder shall give rise to any liability of such
Holder for the Exercise Price of Warrant Shares acquirable by exercise hereof or
as a stockholder of the Company.

        6. Transfer of Warrant.

        (a) Warrant Register. The Company will maintain a register (the "Warrant
Register") containing the names and addresses of the Holder or Holders. Any
Holder of this Warrant or any portion thereof may change his address as shown on
the Warrant Register by written notice to the Company requesting such change.
Any notice or written communication required or permitted to be given to the
Holder may be delivered or given by mail to such Holder as shown on the Warrant
Register and at the address shown on the Warrant Register. Until this Warrant is
transferred on the Warrant Register of the Company, the Company may treat the
Holder as shown on the Warrant Register as the absolute owner of this Warrant
for all purposes, notwithstanding any notice to the contrary.

        (b) Warrant Agent. The Company may, by written notice to the Holder,
appoint an agent for the purpose of maintaining the Warrant Register referred to
in Section 6(a) above, issuing the Warrant Shares or other securities then
issuable upon the exercise of this Warrant, exchanging this Warrant, replacing
this Warrant, or any or all of the foregoing. Thereafter, any such registration,
issuance, exchange, or replacement, as the case may be, shall be made at the
office of such agent.

        (c) Transferability and Nonnegotiability of Warrant. This Warrant may
not be transferred or assigned in whole or in part without compliance with all
applicable federal and state securities laws by the transferor and the
transferee (including the delivery of investment representation letters and
legal opinions reasonably satisfactory to the Company, if such are requested by
the Company). Notwithstanding the foregoing, no investment representation letter
or opinion of counsel shall be required for any transfer of this Warrant (or any
portion thereof) or any shares of Common Stock issued upon exercise hereof or
conversion thereof (i) in compliance with Rule 144 or Rule 144A of the Act, (ii)
by gift, will or intestate succession by the Holder to his or her spouse or
lineal descendants or ancestors or any trust for any of the foregoing, or (iii)
to an affiliate of the Holder, which for purposes of this Warrant shall be
deemed to include any consultant rendering services to Holder in connection with
Holder's services to the Company, provided that such consultant delivers an
investment representation letter to the Company; provided that in each of the
foregoing cases the transferee agrees in writing to be subject to the


                                      -4-


<PAGE>   5
terms of this Section 6(c). Subject to the provisions of this Warrant with
respect to compliance with the Securities Act of 1933, as amended (the "Act"),
title to this Warrant may be transferred by endorsement (by the Holder executing
the Assignment Form annexed hereto) and delivery in the same manner as a
negotiable instrument transferable by endorsement and delivery.

        (d) Exchange of Warrant Upon a Transfer. On surrender of this Warrant
for exchange, properly endorsed on the Assignment Form and subject to the
provisions of this Warrant with respect to compliance with the Act and with the
limitations on assignments and transfers and contained in this Section 6, the
Company at its expense shall issue to or on the order of the Holder a new
warrant or warrants of like tenor, in the name of the Holder or as the Holder
(on payment by the Holder of any applicable transfer taxes) may direct, for the
number of shares issuable upon exercise hereof.

        (e) Compliance with Securities Laws.

                (i) The Holder of this Warrant, by acceptance hereof,
        acknowledges that this Warrant and the shares of Common Stock to be
        issued upon exercise hereof or conversion thereof are being acquired
        solely for the Holder's own account and not as a nominee for any other
        party, and for investment, and that the Holder will not offer, sell or
        otherwise dispose of this Warrant or any shares of Common Stock to be
        issued upon exercise hereof or conversion thereof except under
        circumstances that will not result in a violation of the Act or any
        applicable state securities laws. Upon exercise of this Warrant, the
        Holder shall, if requested by the Company, confirm in writing, in a form
        satisfactory to the Company, that the shares of Common Stock so
        purchased are being acquired solely for the Holder's own account and not
        as a nominee for any other party, for investment, and not with a view
        toward distribution or resale.

                (ii) This Warrant and all shares of Common Stock issued upon
        exercise hereof or conversion thereof shall be stamped or imprinted with
        a legend in substantially the following form (in addition to any legend
        required by state securities laws):

                THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER
                THE SECURITIES ACT OF 1933. SUCH SECURITIES AND ANY SECURITIES
                OR SHARES ISSUED HEREUNDER MAY NOT BE SOLD OR TRANSFERRED IN THE
                ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER
                SAID ACT. COPIES OF THE AGREEMENT COVERING THE ISSUANCE OF THESE
                SECURITIES MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY
                THE HOLDER OF RECORD HEREOF TO THE SECRETARY OF THE COMPANY AT
                ITS PRINCIPAL EXECUTIVE OFFICES.

                (iii) The Company agrees to remove promptly, upon the request of
        the holder of this Warrant and Securities issuable upon exercise of the
        Warrant, the legend set forth in Section 6(e)(ii) above from the
        documents/certificates for such securities upon full compliance with
        this Agreement and Rules 144 and 145.


                                      -5-


<PAGE>   6
        7. Reservation of Stock. The Company covenants that during the Exercise
Period, the Company will reserve from its authorized and unissued Common Stock
or other shares issuable upon exercise of this Warrant a sufficient number of
shares to provide for the issuance of Common Stock upon the exercise of this
Warrant and, from time to time, will take all steps necessary to amend its
Amended and Restated Articles of Incorporation (the "Restated Articles") to
provide sufficient reserves of shares of Common Stock issuable upon exercise of
this Warrant. The Company further covenants that all shares that may be issued
upon the exercise of rights represented by this Warrant and payment of the
Exercise Price, all as set forth herein, will be duly and validly issued, fully
paid and nonassessable and free from all taxes, liens and charges in respect of
the issue thereof (other than taxes in respect of any transfer occurring
contemporaneously or otherwise specified herein). The Company shall take all
such actions as may be necessary to assure that all such shares of Common Stock
may be so issued without violation of any applicable law or governmental
regulation or any requirements of any domestic securities exchange upon which
shares of Common Stock may be listed (except for official notice of issuance
which shall be immediately delivered by the Company upon each such issuance).
The Company shall not take any action which would cause the number of authorized
but unissued shares of Common Stock or other shares issuable upon exercise of
this Warrant to be less than the number of such shares required to be reserved
hereunder for issuance upon exercise of this Warrant.

        8. Notices.

        (a) Whenever the Exercise Price or number of shares purchasable
hereunder shall be adjusted pursuant to Section 10 hereof, the Company shall
issue a certificate signed by its Chief Financial Officer setting forth, in
reasonable detail, the event requiring the adjustment, the amount of the
adjustment, the method by which such adjustment was calculated, and the Exercise
Price and number of shares purchasable hereunder after giving effect to such
adjustment, and shall cause a copy of such certificate to be mailed (by
first-class mail, postage prepaid) to the Holder of this Warrant.

        (b) In case:

                (i) the Company shall take a record of the holders of its Common
        Stock (or other stock or securities at the time receivable upon the
        exercise of this Warrant) for the purpose of entitling them to receive
        any dividend or other distribution, or any right to subscribe for or
        purchase any shares of stock of any class or any other securities, or to
        receive any other right;

                (ii) of any capital reorganization of the Company, any
        reclassification of the capital stock of the Company, any consolidation
        or merger of the Company with or into another corporation, or any
        conveyance of all or substantially all of the assets of the Company to
        another corporation;

                (iii) of any voluntary dissolution, liquidation or winding-up of
        the Company; or

                (iv) of any redemption or conversion of all outstanding Common
        Stock;


                                      -6-


<PAGE>   7
then, and in each such case, the Company will mail or cause to be mailed to the
Holder or Holders a notice specifying, as the case may be, (A) the date on which
a record is to be taken for the purpose of such dividend, distribution or right,
and stating the amount and character of such dividend, distribution or right or
(B) the date on which such reorganization, reclassification, consolidation,
merger, conveyance, dissolution, liquidation, winding-up, redemption or
conversion is to take place, and the time, if any is to be fixed, as of which
the holders of record of Common Stock (or such stock or securities at the time
receivable upon the exercise of this Warrant) shall be entitled to exchange
their shares of Common Stock (or such other stock or securities) for securities
or other property deliverable upon such reorganization, reclassification,
consolidation, merger, conveyance, dissolution, liquidation or winding-up. Such
notice shall be mailed at least fifteen (15) days prior to the date therein
specified.

        (c) All such notices, advices and communications shall be deemed to have
been received (i) in the case of personal delivery, on the date of such delivery
and (ii) in the case of mailing, on the third business day following the date of
such mailing if sent to a U.S. address and on the tenth (10th) business day
following the date of such mailing if sent to an address outside the U.S.

        9. Amendments. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

        10. Adjustments. The Exercise Price and the number of Warrant Shares
purchasable hereunder are subject to adjustment from time to time as follows:

        (a) Reorganization, Reclassification, Consolidation, Merger or Sale. If
any recapitalization, reclassification or reorganization of the capital stock of
the Company, or any consolidation or merger of the Company with another
corporation, or the sale of all or substantially all of its assets or other
transaction shall be effected in such a way that holders of Common Stock shall
be entitled to receive (either directly or upon subsequent liquidation) stock,
securities, or other assets or property (a "Change"), then, as a condition of
such Change, lawful and adequate provisions shall be made by the Company whereby
the Holder hereof shall thereafter have the right to purchase and receive (in
lieu of the shares of the Common Stock of the Company immediately prior to such
Change purchasable and receivable upon the exercise of the rights represented
hereby) such shares of stock, securities or other assets or property as may be
issued or paid with respect to or in exchange for a number of outstanding shares
of such Common Stock equal to the number of shares of such stock immediately
prior to such Change purchaseable and receivable upon the exercise of the rights
represented hereby at the Exercise Price, appropriately adjusted for such
Change. In any such case, the Company shall make appropriate provision with
respect to such holders' rights and interests to insure that the provisions of
this Section 10 shall thereafter be applicable to the Warrants. The Company
shall not effect any such Change, unless prior to the consummation thereof, the
successor entity (if other than the Company) resulting from consolidation or
merger or the entity purchasing such assets assumes by written instrument, the
obligation to deliver to each such holder such shares of stock, securities or
assets as, in accordance with the foregoing provisions, such holder may be
entitled to acquire. Promptly following any Change, and in any event within 20
days thereafter, upon delivery for cancellation of this Warrant, the Holder
shall be issued a successor warrant


                                      -7-


<PAGE>   8
which provides that Holder may exercise such successor warrant, subject to the
same requirements set forth herein, for the kind and amount of stock, securities
or other assets or property as may be issued or payable with respect to or in
exchange immediately after such Change.

        (b) Split, Subdivision or Combination of Shares. If the Company at any
time while this Warrant, or any portion thereof, remains outstanding and
unexpired shall split, subdivide or combine the securities as to which purchase
rights under this Warrant exist, into a different number of securities of the
same class, then (i) in the case of a split or subdivision, the Exercise Price
for such securities shall be proportionately decreased and the securities
issuable upon exercise of this Warrant shall be proportionately increased, and
(ii) in the case of a combination, the Exercise Price for such securities shall
be proportionately increased and the securities issuable upon exercise of this
Warrant shall be proportionately decreased.

        (c) Adjustments for Dividends in Stock or Other Securities or Property;
Purchase Rights. If while this Warrant, or any portion hereof, remains
outstanding and unexpired the holders of the securities as to which purchase
rights under this Warrant exist at the time shall have received, or, on or after
the record date fixed for the determination of eligible Stockholders, shall have
become entitled to receive, without payment therefor, other or additional stock
or other securities or property (other than cash) of the Company by way of
dividend, then and in each case, this Warrant shall represent the right to
acquire, in addition to the number of shares of the security receivable upon
exercise of this Warrant, and without payment of any additional consideration
therefor, the amount of such other or additional stock or other securities or
property (other than cash) of the Company that such holder would hold on the
date of such exercise had it been the holder of record of the security
receivable upon exercise of this Warrant on the date hereof and had thereafter,
during the period from the date hereof to and including the date of such
exercise, retained such shares and/or all other additional stock available by it
as aforesaid during such period, giving effect to all adjustments called for
during such period by the provisions of this Section 10. If at any time the
Company grants, issues or sells any security or right to purchase stock,
warrants, securities or other property pro rata to the holders of the securities
as to which purchase rights under this Warrant exist (the "Purchase Rights"),
then the Holder of this Warrant shall be entitled to acquire, upon the terms
applicable to such Purchase Rights, the aggregate Purchase Rights which such
holder could have acquired if such holder had held the number of shares of
Common Stock acquirable upon complete exercise of this Warrant immediately
before the date on which a record is taken for the grant, issuance or sale of
such Purchase Rights, or, if no such record is taken, the date as of which the
holders of the securities as to which purchase rights under this Warrant exist
are to be determined for the grant, issue or sale of such Purchase Rights.

        (d) Certificate as to Adjustments. Upon the occurrence of each
adjustment or readjustment pursuant to this Section 10, the Company at its
expense shall promptly compute such adjustment or readjustment in accordance
with the terms hereof and furnish to each Holder of this Warrant a certificate
setting forth such adjustment or readjustment and showing in detail the facts
upon which such adjustment or readjustment is based. The Company shall, upon the
written request, at any time, of any such Holder, furnish or cause to be
furnished to such Holder a like certificate setting forth: (i) such adjustments
and readjustments; (ii) the Exercise Price at


                                      -8-


<PAGE>   9
the time in effect; and (iii) the number of shares and the amount, if any, of
other property that at the time would be received upon the exercise of the
Warrant.

        (e) No Impairment; Certain Events. The Company will not, by any
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms to be observed or performed hereunder by the Company, but will at all
times in good faith assist in the carrying out of all the provisions of this
Section 10 and in the taking of all such action as may be necessary or
appropriate in order to protect the rights of the Holders of this Warrant
against impairment. If any event occurs of the type contemplated by the
provisions of this Section 10 but not expressly provided for by such provisions,
then the Company's board of directors shall make an appropriate adjustment in
the Exercise Price or the number of Warrant Shares obtainable upon exercise of
this Warrant so as to protect the rights of the holders of this Warrant;
provided, that no such adjustment shall increase or decrease the number of
Warrant Shares obtainable as otherwise determined pursuant to this Section 10.

        11. Miscellaneous.

        (a) This Warrant shall be governed by the laws of the State of
California as applied to agreements entered into in the State of California by
and among residents of the State of California.

        (b) In the event of a dispute with regard to the interpretation of this
Warrant, the prevailing party may collect the cost of attorney's fees,
litigation expenses or such other expenses as may be incurred in the enforcement
of the prevailing party's rights hereunder.

        (c) This Warrant shall be exercisable as provided for herein, except
that in the event that the expiration date of this Warrant shall fall on a
Saturday, Sunday and or United States federally recognized Holiday, this
expiration date for this Warrant shall be extended to 5:00 p.m. Pacific standard
time on the business day following such Saturday, Sunday or recognized Holiday.


                                      -9-


<PAGE>   10
        IN WITNESS WHEREOF, CRITICAL PATH, INC. has caused this Warrant to be
executed by its officers thereunto duly authorized.

        Dated:  March 29, 2001

                                    CRITICAL PATH, INC.



                                    By  /s/ David C. Hayden
                                        -------------------------------

                                    Title
                                         ------------------------------

                                    VECTIS GROUP, LLC



                                    By   /s/ Matthew Hobart
                                       --------------------------------
                                    Title   CFO
                                         ------------------------------


                                      -10-


<PAGE>   11
                               NOTICE OF EXERCISE

To: CRITICAL PATH, INC.

        (1) The undersigned hereby elects to purchase __________ shares of
Common Stock of CRITICAL PATH, INC., pursuant to the terms of the attached
Warrant, and tenders herewith payment of the purchase price for such shares in
full.

        (2) In exercising this Warrant, the undersigned hereby confirms and
acknowledges that the shares of Common Stock are being acquired solely for the
account of the undersigned and not as a nominee for any other party, or for
investment, and that the undersigned will not offer, sell or otherwise dispose
of any such shares of Common Stock except under circumstances that will not
result in a violation of the Securities Act of 1933, as amended, or any
applicable state securities laws.

        (3) Please issue a certificate or certificates representing said shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:


                         ------------------------------
                                     (Name)


                         ------------------------------
                                     (Name)

        (4) Please issue a new Warrant for the unexercised portion of the
attached Warrant in the name of the undersigned or in such other name as is
specified below:

                                             ------------------------------
                                                         (Name)

-----------------------------                ------------------------------
            (Date)                                     (Signature)


<PAGE>   12
                                 ASSIGNMENT FORM

        FOR VALUE RECEIVED, the undersigned registered owner of this Warrant
hereby sells, assigns and transfers unto the Assignee named below all of the
rights of the undersigned under the within Warrant, with respect to the number
of shares of Common Stock set forth below:


<TABLE>
<CAPTION>
                                                                       No. of
         Name of Assignee                        Address               Shares
         ----------------                        -------               ------
<S>                                              <C>                   <C>

</TABLE>


and does hereby irrevocably constitute and appoint Attorney ________________ to
make such transfer on the books of CRITICAL PATH, INC., maintained for the
purpose, with full power of substitution in the premises.

        The undersigned also represents that, by assignment hereof, the Assignee
acknowledges that this Warrant and the shares of stock to be issued upon
exercise hereof are being acquired for investment and that the Assignee will not
offer, sell or otherwise dispose of this Warrant or any shares of stock to be
issued upon exercise hereof except under circumstances which will not result in
a violation of the Securities Act of 1933, as amended, or any applicable state
securities laws. Further, the Assignee has acknowledged that upon exercise of
this Warrant, the Assignee shall, if requested by the Company, confirm in
writing, in a form satisfactory to the Company, that the shares of stock so
purchased are being acquired for investment and not with a view toward
distribution or resale.

        Dated:                ,     .
                --------------  ----

                                                ------------------------
                                                   Signature of Holder