CVE-2026-113726: high-severity vulnerability in pypa virtualenv
virtualenv activate runs commands from the environment name in zsh with PROMPT_SUBST
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.8epss 0.3%
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/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected products
pypa · virtualenvRelated CVEs — pypa virtualenv
In the same product, most dangerous first.
CVE-2026-113717LOWvirtualenv: Pip seeding with download omits wheel digest verificationEPSS 0.3%CVE-2026-113722HIGHvirtualenv: Generated POSIX console launchers interpret destination paths as shell syntaxEPSS 0.3%CVE-2026-115586HIGHvirtualenv: Bash activator leaves the --prompt value unescaped in PS1 when promptvars is off, so prompt expansion later executes it (regression in 21.14.9)EPSS 0.3%CVE-2026-113776HIGHvirtualenv activation scripts run code from a path that contains a placeholder nameEPSS 0.3%CVE-2026-113725HIGHvirtualenv bash activate runs commands from an environment name with a backslash before $EPSS 0.3%CVE-2026-113714LOWvirtualenv: Downloaded wheel selection and caching precede verificationEPSS 0.2%