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Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M

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

High 7.8

In plain English

A high-severity OS command injection in virtualenv from pypa. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 85.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12python-virtualenvno fix listedDEBIAN-CVE-2026-113732
Debian:13python-virtualenvno fix listedDEBIAN-CVE-2026-113732
Debian:14python-virtualenvno fix listedDEBIAN-CVE-2026-113732
PyPIvirtualenv21.14.2GHSA-c947-3pg5-gm8q
Ubuntu:26.04:LTSpython-virtualenvno fix listedUBUNTU-CVE-2026-113732
Ubuntu:26.10python-virtualenvno fix listedUBUNTU-CVE-2026-113732

Affected products (as reported)

VendorProductVersions
pypa virtualenv < 21.14.2

Weakness: CWE-78, CWE-116 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References