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Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M

CVE-2026-113718virtualenv: Xonsh activation literals depend on the script decoding codec

High 7.1

In plain English

A high-severity code injection in virtualenv from pypa. Proof-of-concept exploit code is public. 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 4.0)7.1High
Exploit odds (30 days)0.2%top 84.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, POSIX xonsh activation quote() uses repr() to write printable non-ASCII prompt or destination data into UTF-8 activate.xsh, while xonsh can read that script using $XONSH_ENCODING. Under a legacy multibyte codec such as GBK or Big5, a UTF-8 trail byte can consume the backslash before an adjacent quote, allowing the literal to close and attacker-influenced statements to execute when the user sources the generated script. This issue is fixed in version 21.14.9.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12python-virtualenvno fix listedDEBIAN-CVE-2026-113718
Debian:13python-virtualenvno fix listedDEBIAN-CVE-2026-113718
Debian:14python-virtualenvno fix listedDEBIAN-CVE-2026-113718
PyPIvirtualenv21.14.9GHSA-394h-qwmc-48pf
Ubuntu:26.04:LTSpython-virtualenvno fix listedUBUNTU-CVE-2026-113718
Ubuntu:26.10python-virtualenvno fix listedUBUNTU-CVE-2026-113718

Affected products (as reported)

VendorProductVersions
pypa virtualenv < 21.14.9

Weakness: CWE-94 · 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