CVE-2026-113718
7.1HighPublished 20 Oct 2026 · NVD status: Received · AI triage by gemini-3.8-flash
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- None
- User interaction
- Active
- Impact
- Full C/I/A compromise
- Weakness
- CWE-94
Impact
An attacker who can control directory names or prompts can execute arbitrary code in a victim's shell. This triggers when a user sources a poisoned activate.xsh file in xonsh using a legacy multibyte encoding.
Root cause
Improper escaping in POSIX xonsh activation script generation lets multibyte encodings consume quote-escaping backslashes, breaking out of quoted literals.
Affected systems
virtualenv prior to 21.14.9
CVSS v4.0 · 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Fix & remediation
Upgrade virtualenv to version 21.14.9 or higher and regenerate existing virtual environment activation scripts.
$ pip install --upgrade 'virtualenv>=21.14.9'AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD 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.