What’s Vulnerable › Vulnerabilities

CVE-2026-113732: virtualenv activate.fish runs commands from a path or prompt with a backslash before a quote

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-27
• Weakness: CWE-78

Description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.2, FishActivator inherits ViaTemplateActivator.quote(), which uses POSIX shlex.quote() even though fish interprets backslashes and single quotes differently. An attacker-influenced environment path, --prompt, or VIRTUALENV_PROMPT value containing a backslash before a quote can therefore terminate the generated fish literal and execute command substitution when the user sources activate.fish. This issue is fixed in version 21.14.2.

Affected products

• Pypi Virtualenv: before 21.14.2; 0.8, 0.8.1, 0.8.2, 0.8.3, 0.8.4, 0.9 (+291) — fixed in 21.14.2
• pypa virtualenv: before 21.14.2

How to fix

Upgrade to a fixed version: Pypi Virtualenv 21.14.2. Check the vendor advisory for mitigations.

References

• https://github.com/pypa/virtualenv/commit/3bddeaf8d02c3ee7f576503efb082f8f494cfcab
• https://github.com/pypa/virtualenv/releases/tag/21.14.2
• https://github.com/pypa/virtualenv/security/advisories/GHSA-c947-3pg5-gm8q

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