pypa virtualenv up to 21.14.8 Symlink pyvenv.cfg ViaTemplateActivator._generate/PyEnvCfg.write link following

CVSS Meta Temp Score
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CTI Interest Score
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4.8$0-$5k1.72

Summaryinfo

A vulnerability, which was classified as problematic, was found in pypa virtualenv up to 21.14.8. Affected by this issue is the function ViaTemplateActivator._generate/PyEnvCfg.write of the file pyvenv.cfg of the component Symlink Handler. Such manipulation leads to link following. This vulnerability is traded as CVE-2026-113721. An attack has to be approached locally. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in pypa virtualenv up to 21.14.8. Affected by this issue is the function ViaTemplateActivator._generate/PyEnvCfg.write of the file pyvenv.cfg of the component Symlink Handler. The manipulation with an unknown input leads to a link following vulnerability. Using CWE to declare the problem leads to CWE-59. 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, ViaTemplateActivator._generate() removes an existing output only when Path.exists() is true, allowing a dangling symlink to survive and redirect generated activation content, while PyEnvCfg.write() opens pyvenv.cfg without first replacing an existing symbolic or hard link. Another local account that prepares final entries inside the destination can therefore cause environment creation to create or overwrite files outside the requested tree with constrained virtualenv-generated content and the invoking user's permissions. The destination parent must remain controlled by the environment owner during creation; concurrent parent-directory replacement is a separate concern. This issue is fixed in version 21.14.9.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-113721 since 10/20/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 21.14.9 eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.8

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Link following
CWE: CWE-59
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: virtualenv 21.14.9

Timelineinfo

10/20/2026 Advisory disclosed
10/20/2026 +0 days CVE reserved
10/20/2026 +0 days VulDB entry created
10/20/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-113721 (🔒)
GCVE (CVE): GCVE-0-2026-113721
GCVE (VulDB): GCVE-100-422984

Entryinfo

Created: 10/20/2026 22:11
Changes: 10/20/2026 22:11 (66)
Complete: 🔍
Cache ID: 216::103

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