The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Resultant

Soft links are a UNIX term that is synonymous with simple shortcuts on Windows-based platforms.

insecure temporary file
Some people use the phrase "insecure temporary file" when referring to a link following weakness, but other weaknesses can produce insecure temporary files without any symlink involvement at all.

Zip Slip
"Zip slip" is an attack that uses file archives (e.g., ZIP, tar, rar, etc.) that contain filenames with path traversal sequences that cause the files to be written outside of the directory under which the archive is expected to be extracted [REF-1282]. It is most commonly used for relative path traversal (CWE-23) and link following (CWE-59).

Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Medium

Confidentiality
Integrity
Access Control
Read Files or Directories
Modify Files or Directories
Bypass Protection Mechanism
An attacker may be able to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. If the files are used for a security mechanism then an attacker may be able to bypass the mechanism.

Other
Execute Unauthorized Code or Commands
Windows simple shortcuts, sometimes referred to as soft links, can be exploited remotely since a ".LNK" file can be uploaded like a normal file. This can enable remote execution.

Automated Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

SOAR Partial

Manual Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner
Web Services Scanner
Database Scanners

SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester
Framework-based Fuzzer

SOAR Partial

Manual Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Focused Manual Spotcheck - Focused manual analysis of source
Manual Source Code Review (not inspections)

High

Automated Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Source code Weakness Analyzer
Context-configured Source Code Weakness Analyzer

SOAR Partial

Architecture or Design Review

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

High

Architecture and Design
Separation of Privilege

Follow the principle of least privilege when assigning access rights to entities in a software system.
Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

CVE-1999-1386
Some versions of Perl follow symbolic links when running with the -e option, which allows local users to overwrite arbitrary files via a symlink attack.
https://www.cve.org/CVERecord?id=CVE-1999-1386

CVE-2000-1178
Text editor follows symbolic links when creating a rescue copy during an abnormal exit, which allows local users to overwrite the files of other users.
https://www.cve.org/CVERecord?id=CVE-2000-1178

CVE-2004-0217
Antivirus update allows local users to create or append to arbitrary files via a symlink attack on a logfile.
https://www.cve.org/CVERecord?id=CVE-2004-0217

CVE-2003-0517
Symlink attack allows local users to overwrite files.
https://www.cve.org/CVERecord?id=CVE-2003-0517

CVE-2004-0689
Window manager does not properly handle when certain symbolic links point to "stale" locations, which could allow local users to create or truncate arbitrary files.
https://www.cve.org/CVERecord?id=CVE-2004-0689

CVE-2005-1879
Second-order symlink vulnerabilities
https://www.cve.org/CVERecord?id=CVE-2005-1879

CVE-2005-1880
Second-order symlink vulnerabilities
https://www.cve.org/CVERecord?id=CVE-2005-1880

CVE-2005-1916
Symlink in Python program
https://www.cve.org/CVERecord?id=CVE-2005-1916

CVE-2000-0972
Setuid product allows file reading by replacing a file being edited with a symlink to the targeted file, leaking the result in error messages when parsing fails.
https://www.cve.org/CVERecord?id=CVE-2000-0972

CVE-2005-0824
Signal causes a dump that follows symlinks.
https://www.cve.org/CVERecord?id=CVE-2005-0824

CVE-2001-1494
Hard link attack, file overwrite; interesting because program checks against soft links
https://www.cve.org/CVERecord?id=CVE-2001-1494

CVE-2002-0793
Hard link and possibly symbolic link following vulnerabilities in embedded operating system allow local users to overwrite arbitrary files.
https://www.cve.org/CVERecord?id=CVE-2002-0793

CVE-2003-0578
Server creates hard links and unlinks files as root, which allows local users to gain privileges by deleting and overwriting arbitrary files.
https://www.cve.org/CVERecord?id=CVE-2003-0578

CVE-1999-0783
Operating system allows local users to conduct a denial of service by creating a hard link from a device special file to a file on an NFS file system.
https://www.cve.org/CVERecord?id=CVE-1999-0783

CVE-2004-1603
Web hosting manager follows hard links, which allows local users to read or modify arbitrary files.
https://www.cve.org/CVERecord?id=CVE-2004-1603

CVE-2004-1901
Package listing system allows local users to overwrite arbitrary files via a hard link attack on the lockfiles.
https://www.cve.org/CVERecord?id=CVE-2004-1901

CVE-2005-1111
Hard link race condition
https://www.cve.org/CVERecord?id=CVE-2005-1111

CVE-2000-0342
Mail client allows remote attackers to bypass the user warning for executable attachments such as .exe, .com, and .bat by using a .lnk file that refers to the attachment, aka "Stealth Attachment."
https://www.cve.org/CVERecord?id=CVE-2000-0342

CVE-2001-1042
FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.
https://www.cve.org/CVERecord?id=CVE-2001-1042

CVE-2001-1043
FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.
https://www.cve.org/CVERecord?id=CVE-2001-1043

CVE-2005-0587
Browser allows remote malicious web sites to overwrite arbitrary files by tricking the user into downloading a .LNK (link) file twice, which overwrites the file that was referenced in the first .LNK file.
https://www.cve.org/CVERecord?id=CVE-2005-0587

CVE-2001-1386
".LNK." - .LNK with trailing dot
https://www.cve.org/CVERecord?id=CVE-2001-1386

CVE-2003-1233
Rootkits can bypass file access restrictions to Windows kernel directories using NtCreateSymbolicLinkObject function to create symbolic link
https://www.cve.org/CVERecord?id=CVE-2003-1233

CVE-2002-0725
File system allows local attackers to hide file usage activities via a hard link to the target file, which causes the link to be recorded in the audit trail instead of the target file.
https://www.cve.org/CVERecord?id=CVE-2002-0725

CVE-2003-0844
Web server plugin allows local users to overwrite arbitrary files via a symlink attack on predictable temporary filenames.
https://www.cve.org/CVERecord?id=CVE-2003-0844

CVE-2015-3629
A Libcontainer used in Docker Engine allows local users to escape containerization and write to an arbitrary file on the host system via a symlink attack in an image when respawning a container.
https://www.cve.org/CVERecord?id=CVE-2015-3629

CVE-2021-21272
"Zip Slip" vulnerability in Go-based Open Container Initiative (OCI) registries product allows writing arbitrary files outside intended directory via symbolic links or hard links in a gzipped tarball.
https://www.cve.org/CVERecord?id=CVE-2021-21272

CVE-2020-27833
"Zip Slip" vulnerability in container management product allows writing arbitrary files outside intended directory via a container image (.tar format) with filenames that are symbolic links that point to other files within the same tar file; however, the files being pointed to can also be symbolic links to destinations outside the intended directory, bypassing the initial check.
https://www.cve.org/CVERecord?id=CVE-2020-27833

File Processing

File or Directory

Link Following

FIO02-C
Canonicalize path names originating from untrusted sources

POS01-C
Check for the existence of links when dealing with files

FIO01-PL
Do not operate on files that can be modified by untrusted users
CWE More Specific

SFP18
Link in resource name resolution

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.

Link following vulnerabilities are Multi-factor Vulnerabilities (MFV). They are the combination of multiple elements: file or directory permissions, filename predictability, race conditions, and in some cases, a design limitation in which there is no mechanism for performing atomic file creation operations.
Some potential factors are race conditions, permissions, and predictability.

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

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Alternate_Terms, Applicable_Platforms, Relationships, Other_Notes, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities

CWE Content Team
MITRE
2008-11-24
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2009-01-12
updated Relationships

CWE Content Team
MITRE
2009-05-27
updated Description, Name

CWE Content Team
MITRE
2009-10-29
updated Background_Details, Other_Notes

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

CWE Content Team
MITRE
2010-04-05
updated Related_Attack_Patterns

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2011-09-13
updated Relationships, Taxonomy_Mappings

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

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations

CWE Content Team
MITRE
2014-06-23
updated Common_Consequences, Other_Notes

CWE Content Team
MITRE
2014-07-30
updated Detection_Factors, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2015-12-07
updated Relationships

CWE Content Team
MITRE
2017-11-08
updated Affected_Resources, Applicable_Platforms, Causal_Nature, Common_Consequences, Functional_Areas, Likelihood_of_Exploit, Modes_of_Introduction, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2019-01-03
updated Taxonomy_Mappings

CWE Content Team
MITRE
2019-06-20
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated Relationships

CWE Content Team
MITRE
2021-03-15
updated Relationships

CWE Content Team
MITRE
2021-10-28
updated Relationships

CWE Content Team
MITRE
2022-04-28
updated Research_Gaps

CWE Content Team
MITRE
2022-06-28
updated Relationships

CWE Content Team
MITRE
2022-10-13
updated Alternate_Terms, Background_Details, Observed_Examples, References, Relationship_Notes, Theoretical_Notes

CWE Content Team
MITRE
2023-01-31
updated Description

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-09-09
4.18
2025-09-09
updated Detection_Factors, References

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

Link Following
Failure to Resolve Links Before File Access (aka 'Link Following')