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Vulnerabilities

Security fix · CVE-2026-113716

virtualenv is a tool for creating isolated virtual python environments.

Published Oct 20, 2026 · catalog updated Oct 22, 2026 · virtualenv is a tool

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-113716. EPSS is 0.14%. 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
Medium4.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.14%
Remediation
Version ranges on file
Affected products
pip virtualenv

## Summary The builtin creator accepts existing directory symlinks through ensure_dir() and writes environment files through those directories. This permits writes outside the requested destination. Anthropic's OSS Scanner reported this as in , received on 15 October 2026. ## Affected area Directory preparation before environment files are created. ## Attacker-controlled input Another account must be able to prepare linked entries below the chosen destination before creation. The invoking user must have access to the linked destination. This does not require write access to the target itself under the other account. ## Affected code The relevant 21.14.8 source is in [builtin creator](https://github.com/pypa/virtualenv/blob/a795ab116356afde11039cf2763d77e8a06da738/src/virtualenv/create/via_global_ref/builtin/via_global_self_do.py), [ensure_dir()](https://github.com/pypa/virtualenv/blob/a795ab116356afde11039cf2763d77e8a06da738/src/virtualenv/util/path/_sync.py). ## Mechanism The builtin creator calls for , , and package directories. accepts an existing symlink to a directory because follows it. Interpreter creation, seed installation, and activation-script generation then write through that parent link. A final-file check cannot prevent a write through a linked parent. removes the planted tree first; ordinary creation over a prepared destination reaches it. ## Reproduction and evidence The scanner's project tree contains and a file in the environment's package tree. With the user's initially empty first on , exited successfully and wrote , , and into . The marker was absent immediately after creation; a later on the user's loaded the seeded environment and the planted code wrote the marker. A second case began with the link resolving inside the environment; replacement of a planted package link during seeding changed where it resolved, and writes again reached . The attacker must prepare entries in an existing destination. The content is already attacker-controlled an

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.

  • pip virtualenv< 21.14.9

How to fix CVE-2026-113716

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-2026-113716. EPSS is 0.14%. Act only if a listed version of virtualenv is a tool is installed.

Which versions are affected?

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

What should an analyst verify?

CWE-59: Link Following. EPSS 0.14%. 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 builtin creator calls ensure_dir() for executable, library, and package directories, and ensure_dir() accepts an existing symlink to a directory because exists() follows it. Interpreter creation, seed installation, and activation generation then write through the linked parent outside the requested destin

  2. Oct 21, 2026 · NIST NVD

    Updated

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the builtin creator calls ensure_dir() for executable, library, and package directories, and ensure_dir() accepts an existing symlink to a directory because exists() follows it. Interpreter creation, seed installation, and activation generation then write through the linked parent outside the requested destin

  3. Oct 21, 2026 · GitHub Advisory Database

    Updated

    ## Summary The builtin creator accepts existing directory symlinks through ensure_dir() and writes environment files through those directories. This permits writes outside the requested destination. Anthropic's OSS Scanner reported this as in , received on 15 October 2026. ## Affected area Directory preparation before environment files are created. ## Attacker-controlled input Another account must

  4. Oct 22, 2026 · NIST NVD

    Updated

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the builtin creator calls ensure_dir() for executable, library, and package directories, and ensure_dir() accepts an existing symlink to a directory because exists() follows it. Interpreter creation, seed installation, and activation generation then write through the linked parent outside the requested destin

Sources

  • CVE.orgVulnerability recordCVE-2026-113716

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-113716

    30-day exploitation probability 0.14%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-cw65-gx24-rc82

    virtualenv: Builtin creation follows linked environment directories

    github.com
  • NIST NVDVulnerability recordCVE-2026-113716

    virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the builtin creator calls ensure_dir() for executable, library, and package directories, and ensure_dir() accepts an existing symlink to a directory because exists() follows it. Interpreter

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • NIST NVDOct 22, 2026
  • GitHub Advisory DatabaseOct 22, 2026
  • CVE.orgOct 21, 2026