CVE-2026-113726

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.13.0, the bash activate script that zsh also sources leaves the environment name unescaped; from 21.13.0 until 21.14.4, it escapes backslashes, dollar signs, and backticks only when BASH_VERSION is set, so zsh receives the raw value. The script assigns that value to PS1. In zsh with PROMPT_SUBST, an attacker-influenced environment directory, --prompt, or VIRTUALENV_PROMPT value containing command, parameter, or arithmetic expansion syntax can therefore execute commands in the user's shell each time the prompt is drawn. A percent sign is separately interpreted as a zsh prompt escape but does not by itself execute commands. Plain zsh with PROMPT_SUBST disabled and bash are not affected by this mechanism. This issue is fixed in version 21.14.4.

CVSS 3.1

7.8CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.3% chance of exploitation in the next 30 days; higher than 17% of CVEs (scores of 2026-10-25)

CWEs

CWE-78, CWE-116

Published

2026-10-20

Modified

2026-10-22

Record from

the NVD, synced 2026-10-23

Packages (OSV)

References

• https://github.com/pypa/virtualenv/commit/5b915367da82bd024b2a0d28d2f98007034b4aa2
• https://github.com/pypa/virtualenv/releases/tag/21.14.4
• https://github.com/pypa/virtualenv/security/advisories/GHSA-5vjq-rrrf-7h2q

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