RCE in Pypa Virtualenv

CVE-2026-113732

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.

Vulnerability class: Command Injection (OS Command Injection)

Published .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-113732?
CVE-2026-113732 is a high-severity vulnerability in Pypa Virtualenv, classified under OS Command Injection. CVSS score: 7.8/10. Published 2026-10-20.
How severe is CVE-2026-113732?
High severity. CVSS v3 base score is 7.8 out of 10.