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Vulnerability · Published Sep 29, 2026 · Assigned by GitHub_M

CVE-2026-102925virtualenv bash and fish activation scripts execute commands embedded in paths

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 5% 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 95.0% 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 21.7.13, the generated activate (bash and zsh) and activate.fish scripts place values already escaped by shlex.quote inside an additional quoted context. In the bash and zsh script, a crafted virtual environment path reaches __VIRTUAL_ENV__ when a relocated environment's recorded directory is absent; in the fish script, crafted Tcl or Tk library paths reach __TCL_LIBRARY__ or __TK_LIBRARY__. The surplus quotes can terminate the data-only quoted run and leave shell metacharacters parsed as commands when a user sources the activation script, allowing code execution with that user's privileges. This issue is fixed in version 21.7.13.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13python-virtualenvno fix listedDEBIAN-CVE-2026-102925
Debian:14python-virtualenvno fix listedDEBIAN-CVE-2026-102925
PyPIvirtualenv21.7.13GHSA-p58f-9548-mpm2
PyPIvirtualenv21.7.13PYSEC-2026-4013
Ubuntu:26.04:LTSpython-virtualenvno fix listedUBUNTU-CVE-2026-102925
Ubuntu:26.10python-virtualenvno fix listedUBUNTU-CVE-2026-102925

Affected products (as reported)

VendorProductVersions
pypa virtualenv < 21.7.13

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

References