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Vulnerability · Published Oct 23, 2026 · Assigned by GitHub_M

CVE-2026-115586virtualenv: Bash activator leaves the --prompt value unescaped in PS1 when promptvars is off, so prompt expansion later executes it (regression in 21.14.9)

High 7.1

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 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.1High
Exploit odds (30 days)0.3%top 80.6% 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. From 21.14.9 until 21.14.13, the bash bin/activate script can copy an attacker-controlled --prompt value into PS1 without escaping dollar signs or backticks when both promptvars and POSIX mode are disabled during activation. Re-enabling promptvars, running set -o posix, or starting an interactive child bash that inherits the exported PS1 can then expand command substitution in the stored VIRTUAL_ENV_PROMPT value and execute commands as the user who activates the environment. This issue is fixed in version 21.14.13.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIvirtualenv21.14.13GHSA-cx6f-vjhg-g3cc
Ubuntu:26.04:LTSpython-virtualenvno fix listedUBUNTU-CVE-2026-115586
Ubuntu:26.10python-virtualenvno fix listedUBUNTU-CVE-2026-115586

Affected products (as reported)

VendorProductVersions
pypa virtualenv >= 21.14.9, < 21.14.13

Weakness: CWE-78 · Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References