CVE-2026-113726 virtualenv activate runs commands from the environment name in zsh with PROMPT_SUBST
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-113726?
CVE-2026-113726 is a high-severity vulnerability in pypa virtualenv, published on 20 Oct 2026.
Official description
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.
Which versions are affected by CVE-2026-113726?
3 open source packages ship an affected version, including virtualenv.
| Package | Affected | Fixed in |
|---|---|---|
virtualenv Bitnami | All versions | 21.14.4 |
virtualenv PyPI | All versions | 21.14.4 |
virtualenv PyPI | All versions | 21.14.4 |
How do I fix CVE-2026-113726?
Upgrade virtualenv to 21.14.4 or later.
Is CVE-2026-113726 being exploited?
There is no known exploitation of CVE-2026-113726 in the wild and no public exploit code.
Sources
Also known as AZL-110076, AZL-110100, BIT-virtualenv-2026-113726, DEBIAN-CVE-2026-113726, ECHO-bef4-55b6-f81b, GHSA-5vjq-rrrf-7h2q and 3 more.