CVE-2026-113718
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.18%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 7.1 HIGHCVSS: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/M
- EPSS
- 0.18% probability · 7th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-94
- Source
- security-advisories@github.com
EPSS moved from 0.1% on 21 October 2026 to 0.2% on 26 October 2026.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.