What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-27
• Weakness: CWE-94

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 products

• Pypi Virtualenv: before 21.14.9; 0.8, 0.8.1, 0.8.2, 0.8.3, 0.8.4, 0.9 (+298) — fixed in 21.14.9
• pypa virtualenv: before 21.14.9

How to fix

Upgrade to a fixed version: Pypi Virtualenv 21.14.9. Check the vendor advisory for mitigations.

References

• https://github.com/pypa/virtualenv/commit/e5fc2e6e189a877ff559af288919e3525d13e5e0
• https://github.com/pypa/virtualenv/pull/3432
• https://github.com/pypa/virtualenv/releases/tag/21.14.9
• https://github.com/pypa/virtualenv/security/advisories/GHSA-394h-qwmc-48pf
• https://github.com/pypa/virtualenv/security/advisories/GHSA-394h-qwmc-48pf

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