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Vulnerabilities

Security fix · CVE-2026-113720

virtualenv is a tool for creating isolated virtual python environments.

Published Oct 20, 2026 · catalog updated Oct 23, 2026 · virtualenv is a tool

Last checked Nov 3, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-113720. EPSS is 0.13%. Act only if a listed version of virtualenv is a tool is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (virtualenv is a tool).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.13%
Remediation
Version ranges on file
Affected products
PyPI virtualenv · package pip · pip virtualenv · pypi virtualenv

## Summary The app-data copy seeder uses shutil.copy, which preserves cached file modes independently of the current umask. A cache populated under permissive permissions can therefore produce files with wider access in later environments. Anthropic's OSS Scanner reported this as in , received on 15 October 2026. ## Affected area Permissions of files copied from app-data into a new environment. ## Attacker-controlled input The cache must contain files created with broader permissions than the current environment creator intends. Another account must also be able to traverse the new environment and reach those files. A private parent directory prevents that access. No control of a private live cache is assumed. ## Affected code The relevant 21.14.8 source is in [copy helpers](https://github.com/pypa/virtualenv/blob/a795ab116356afde11039cf2763d77e8a06da738/src/virtualenv/util/path/_sync.py). ## Mechanism The default app-data seeder extracts a wheel into a reusable cache and copies its files into later environments with . That function applies the cached source mode to each destination file after creating it, overriding the current run's umask. If the cache image was built under umask , a later environment created under umask can receive mode- pip files. The cache may be private while the new environment is reachable by other local accounts. ## Reproduction and evidence The scanner created two histories with separate private app-data caches. In the control, the owner's first run used umask ; a later environment had no files writable by another account, and that account could not append to . In the attack history, the first run used umask and the later run still used . The report counted 478 of 493 environment files writable by others. A second unprivileged uid appended a line to pip, and ran it as the environment owner. The cache itself remained under a mode- home in both histories. An attacker cannot force the owner's earlier umask through this finding; the attack als

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • PyPI virtualenv0 → 21.14.9
  • package pipversion unspecified
  • pip virtualenv< 21.14.9
  • pypi virtualenvversion unspecified

How to fix CVE-2026-113720

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-113720. EPSS is 0.13%. Act only if a listed version of virtualenv is a tool is installed.

Which versions are affected?

Compare what you have installed with 0 → 21.14.9, < 21.14.9. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-732: Incorrect Permission Assignment for Critical Resource. EPSS 0.13%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 20, 2026 · NIST NVD

    Detected

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the app-data copy seeder uses shutil.copy() to copy cached package files into later environments, causing cached source modes to override the current run's umask. A cache populated under a permissive umask can therefore produce files writable by another local account in a later traversable environment, allowi

  2. Oct 21, 2026 · NIST NVD

    Updated

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the app-data copy seeder uses shutil.copy() to copy cached package files into later environments, causing cached source modes to override the current run's umask. A cache populated under a permissive umask can therefore produce files writable by another local account in a later traversable environment, allowi

  3. Oct 22, 2026 · NIST NVD

    Updated

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the app-data copy seeder uses shutil.copy() to copy cached package files into later environments, causing cached source modes to override the current run's umask. A cache populated under a permissive umask can therefore produce files writable by another local account in a later traversable environment, allowi

  4. Oct 23, 2026 · GitHub Advisory Database

    Updated

    ## Summary The app-data copy seeder uses shutil.copy, which preserves cached file modes independently of the current umask. A cache populated under permissive permissions can therefore produce files with wider access in later environments. Anthropic's OSS Scanner reported this as in , received on 15 October 2026. ## Affected area Permissions of files copied from app-data into a new environment. ##

  5. Oct 23, 2026 · PyPA Advisory Database

    Fix available

    virtualenv fixed in 21.14.9

  6. Oct 23, 2026 · PyPA Advisory Database

    Fix available

    virtualenv fixed in 21.14.9

  7. Oct 23, 2026 · PyPA Advisory Database

    Updated

    ## Summary The app-data copy seeder uses shutil.copy, which preserves cached file modes independently of the current umask. A cache populated under permissive permissions can therefore produce files with wider access in later environments. Anthropic's OSS Scanner reported this as in , received on 15 October 2026. ## Affected area Permissions of files copied from app-data into a new environment. ##

Sources

  • CVE.orgVulnerability recordCVE-2026-113720

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-113720

    30-day exploitation probability 0.13%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-fc2g-4w5p-6whm

    virtualenv: Seeded files retain permissions from an older cache

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-113720

    The app-data copy seeder uses shutil.copy, which preserves cached file modes independently of the current umask. A cache populated under permissive permissions can therefore produce files with wider access in later environments. Anthropic's OSS Scanner reported this as ANT-2026-487MH6OW in virtualenv-20261015-005, received on 15 October 2026.

    advisories.gitlab.com
  • NIST NVDVulnerability recordCVE-2026-113720

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the app-data copy seeder uses shutil.copy() to copy cached package files into later environments, causing cached source modes to override the current run's umask. A cache populated under a p

    nvd.nist.gov
  • PyPA Advisory DatabasePackage advisoryGHSA-fc2g-4w5p-6whm

    virtualenv: Seeded files retain permissions from an older cache

    osv.dev
  • Snyk Vulnerability DatabasePackage advisorySNYK-PYTHON-VIRTUALENV-21282511

    Incorrect Permission Assignment for Critical Resource

    security.snyk.io

References

Freshness

Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 3, 2026
  • GitLab Advisory DatabaseOct 27, 2026
  • PyPA Advisory DatabaseOct 25, 2026
  • GitHub Advisory DatabaseOct 24, 2026
  • Snyk Vulnerability DatabaseOct 23, 2026
  • NIST NVDOct 22, 2026
  • CVE.orgOct 21, 2026