The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
If an attacker can manipulate the length parameter associated with an input such that it is inconsistent with the actual length of the input, this can be leveraged to cause the target application to behave in unexpected, and possibly, malicious ways. One of the possible motives for doing so is to pass in arbitrarily large input to the application. Another possible motivation is the modification of application state by including invalid data for subsequent properties of the application. Such weaknesses commonly lead to attacks such as buffer overflows and execution of arbitrary code.

Primary

length manipulation

length tampering

Implementation

Confidentiality
Integrity
Read Memory
Modify Memory
Varies by Context

Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
High

Implementation
When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.

Implementation
Do not let the user control the size of the buffer.

Implementation
Validate that the length of the user-supplied data is consistent with the buffer size.

In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.

int processMessageFromSocket(int socket) {
int success;
char buffer[BUFFER_SIZE];char message[MESSAGE_SIZE];

// get message from socket and store into buffer

//Ignoring possibliity that buffer > BUFFER_SIZE
if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {

// place contents of the buffer into message structure
ExMessage *msg = recastBuffer(buffer);

// copy message body into string for processing
int index;for (index = 0; index < msg->msgLength; index++) {message[index] = msg->msgBody[index];}message[index] = '\0';

// process message
success = processMessage(message);
}return success;
}

However, the message length variable (msgLength) from the structure is used as the condition for ending the for loop without validating that msgLength accurately reflects the actual length of the message body (CWE-606). If msgLength indicates a length that is longer than the size of a message body (CWE-130), then this can result in a buffer over-read by reading past the end of the buffer (CWE-126).

CVE-2014-0160
Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.
https://www.cve.org/CVERecord?id=CVE-2014-0160

CVE-2009-2299
Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.
https://www.cve.org/CVERecord?id=CVE-2009-2299

CVE-2001-0825
Buffer overflow in internal string handling routine allows remote attackers to execute arbitrary commands via a length argument of zero or less, which disables the length check.
https://www.cve.org/CVERecord?id=CVE-2001-0825

CVE-2001-1186
Web server allows remote attackers to cause a denial of service via an HTTP request with a content-length value that is larger than the size of the request, which prevents server from timing out the connection.
https://www.cve.org/CVERecord?id=CVE-2001-1186

CVE-2001-0191
Service does not properly check the specified length of a cookie, which allows remote attackers to execute arbitrary commands via a buffer overflow, or brute force authentication by using a short cookie length.
https://www.cve.org/CVERecord?id=CVE-2001-0191

CVE-2003-0429
Traffic analyzer allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.
https://www.cve.org/CVERecord?id=CVE-2003-0429

CVE-2000-0655
Chat client allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
https://www.cve.org/CVERecord?id=CVE-2000-0655

CVE-2004-0492
Server allows remote attackers to cause a denial of service and possibly execute arbitrary code via a negative Content-Length HTTP header field causing a heap-based buffer overflow.
https://www.cve.org/CVERecord?id=CVE-2004-0492

CVE-2004-0201
Help program allows remote attackers to execute arbitrary commands via a heap-based buffer overflow caused by a .CHM file with a large length field
https://www.cve.org/CVERecord?id=CVE-2004-0201

CVE-2003-0825
Name services does not properly validate the length of certain packets, which allows attackers to cause a denial of service and possibly execute arbitrary code. Can overlap zero-length issues
https://www.cve.org/CVERecord?id=CVE-2003-0825

CVE-2004-0095
Policy manager allows remote attackers to cause a denial of service (memory consumption and crash) and possibly execute arbitrary code via an HTTP POST request with an invalid Content-Length value.
https://www.cve.org/CVERecord?id=CVE-2004-0095

CVE-2004-0826
Heap-based buffer overflow in library allows remote attackers to execute arbitrary code via a modified record length field in an SSLv2 client hello message.
https://www.cve.org/CVERecord?id=CVE-2004-0826

CVE-2004-0808
When domain logons are enabled, server allows remote attackers to cause a denial of service via a SAM_UAS_CHANGE request with a length value that is larger than the number of structures that are provided.
https://www.cve.org/CVERecord?id=CVE-2004-0808

CVE-2002-1357
Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code.
https://www.cve.org/CVERecord?id=CVE-2002-1357

CVE-2004-0774
Server allows remote attackers to cause a denial of service (CPU and memory exhaustion) via a POST request with a Content-Length header set to -1.
https://www.cve.org/CVERecord?id=CVE-2004-0774

CVE-2004-0989
Multiple buffer overflows in xml library that may allow remote attackers to execute arbitrary code via long URLs.
https://www.cve.org/CVERecord?id=CVE-2004-0989

CVE-2004-0568
Application does not properly validate the length of a value that is saved in a session file, which allows remote attackers to execute arbitrary code via a malicious session file (.ht), web site, or Telnet URL contained in an e-mail message, triggering a buffer overflow.
https://www.cve.org/CVERecord?id=CVE-2004-0568

CVE-2003-0327
Server allows remote attackers to cause a denial of service via a remote password array with an invalid length, which triggers a heap-based buffer overflow.
https://www.cve.org/CVERecord?id=CVE-2003-0327

CVE-2003-0345
Product allows remote attackers to cause a denial of service and possibly execute arbitrary code via an SMB packet that specifies a smaller buffer length than is required.
https://www.cve.org/CVERecord?id=CVE-2003-0345

CVE-2004-0430
Server allows remote attackers to execute arbitrary code via a LoginExt packet for a Cleartext Password User Authentication Method (UAM) request with a PathName argument that includes an AFPName type string that is longer than the associated length field.
https://www.cve.org/CVERecord?id=CVE-2004-0430

CVE-2005-0064
PDF viewer allows remote attackers to execute arbitrary code via a PDF file with a large /Encrypt /Length keyLength value.
https://www.cve.org/CVERecord?id=CVE-2005-0064

CVE-2004-0413
SVN client trusts the length field of SVN protocol URL strings, which allows remote attackers to cause a denial of service and possibly execute arbitrary code via an integer overflow that leads to a heap-based buffer overflow.
https://www.cve.org/CVERecord?id=CVE-2004-0413

CVE-2004-0940
Is effectively an accidental double increment of a counter that prevents a length check conditional from exiting a loop.
https://www.cve.org/CVERecord?id=CVE-2004-0940

CVE-2002-1235
Length field of a request not verified.
https://www.cve.org/CVERecord?id=CVE-2002-1235

CVE-2005-3184
Buffer overflow by modifying a length value.
https://www.cve.org/CVERecord?id=CVE-2005-3184

Length Parameter Inconsistency

SFP24
Tainted Input to Command

Allowed
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

This probably overlaps other categories including zero-length issues.

PLOVER
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Potential_Mitigations, Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Applicable_Platforms, Description, Name, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities

CWE Content Team
MITRE
2009-03-10
updated Description, Name

CWE Content Team
MITRE
2009-12-28
updated Observed_Examples

CWE Content Team
MITRE
2010-02-16
updated Description, Potential_Mitigations, Relationships

CWE Content Team
MITRE
2010-12-13
updated Potential_Mitigations

CWE Content Team
MITRE
2011-03-29
updated Demonstrative_Examples

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2011-06-27
updated Common_Consequences

CWE Content Team
MITRE
2012-05-11
updated Observed_Examples, Relationships

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations

CWE Content Team
MITRE
2013-07-17
updated Type

CWE Content Team
MITRE
2014-06-23
updated Observed_Examples

CWE Content Team
MITRE
2014-07-30
updated Relationships

CWE Content Team
MITRE
2017-01-19
updated Type

CWE Content Team
MITRE
2017-11-08
updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples

CWE Content Team
MITRE
2020-02-24
updated Relationships

CWE Content Team
MITRE
2020-06-25
updated Common_Consequences, Demonstrative_Examples

CWE Content Team
MITRE
2020-08-20
updated Relationships

CWE Content Team
MITRE
2020-12-10
updated Relationships

CWE Content Team
MITRE
2022-10-13
updated Taxonomy_Mappings

CWE Content Team
MITRE
2023-01-31
updated Description

CWE Content Team
MITRE
2023-04-27
updated Relationships, Time_of_Introduction

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2024-02-29
4.14
2024-02-29
updated Observed_Examples

CWE Content Team
MITRE
2025-09-09
4.18
2025-09-09
updated Demonstrative_Examples

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Applicable_Platforms, Detection_Factors

Length Parameter Inconsistency
Failure to Handle Length Parameter Inconsistency