CVE-2026-102938 · GHSA-9h9j-4vrj-gf7g
virtualenv writes prompt values into pyvenv.cfg without sanitizing line boundaries, allowing configuration injection
- Risk score
- 40/100
- CVSS
- 5.8 v4.0
- Exploit chance (30 days)
- 0.1%
- Published
- 29 Sep 2026
Open in the live forecast Today's forecast
What to know
- What it is
- virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.11, PyEnvCfg.write() writes prompt values verbatim to the line-oriented pyvenv.cfg format while PyEnvCfg._read_values() parses the file with str.splitlines() and accepts the last value for duplicate keys. An attacker who influences -…
- Affected
- virtualenv (pip) <= 21.7.10
- Fix
- Upgrade virtualenv to 21.7.11 or later.
- Exploitation
- No known exploitation
Story map
At a glance
virtualenv: Yellow, plan it in. virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.7, the bash activate script escapes the environment name for only one of the two passes bash makes over PS1, so a backslash in the name undoes the escaping and a name containing \$(...) runs as commands in the user's shell each time…
The flaws
- CVE-2026-102938: Virtualenv writes prompt values into pyvenv.cfg without sanitizing line boundaries, allowing configuration injection (CVSS 5.8 · EPSS 0%)
- CVE-2026-113725: Virtualenv bash activate runs commands from an environment name with a backslash before $ (CVSS 7.8 · EPSS 0%)
- CVE-2026-102930: Downloaded seed wheels (pip/setuptools) are not integrity-checked before use (CVSS 7.7 · EPSS 0%)
- CVE-2026-113722: Generated POSIX console launchers interpret destination paths as shell syntax (CVSS 7.8 · EPSS 0%)
The fix
Upgrade virtualenv: 21.7.11 · 21.14.7 · 21.7.12 · 21.14.9 or later on your release line
Who is exposed: virtualenv (pip) <= 21.14.6
Where it stands
- Public proof of concept
Connects to
- Same weakness: CWE-93 (CWE-93). 21 other warnings in 30 days
Why it is Yellow
- CVSS 5.8 medium
- On your watchlist: PyPI
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| virtualenv | pip | <= 21.7.10 | 21.7.11 |
References
- https://github.com/advisories/GHSA-9h9j-4vrj-gf7g
- https://github.com/pypa/virtualenv/security/advisories/GHSA-9h9j-4vrj-gf7g
- https://nvd.nist.gov/vuln/detail/CVE-2026-102938
- https://github.com/pypa/virtualenv/pull/3247
- https://github.com/pypa/virtualenv/commit/a30f995461043acb6cacbf3a890951563ccf7140
- https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4012.yaml
- https://github.com/pypa/virtualenv/releases/tag/21.7.11
- https://pypi.org/project/virtualenv
- https://github.com/advisories/GHSA-9h9j-4vrj-gf7g
Original description
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.11, PyEnvCfg.write() writes prompt values verbatim to the line-oriented pyvenv.cfg format while PyEnvCfg._read_values() parses the file with str.splitlines() and accepts the last value for duplicate keys. An attacker who influences --prompt, VIRTUALENV_PROMPT, or configuration input can insert a recognized line boundary and additional keys, including home, causing consumers to use an attacker-selected base interpreter or corrupted environment metadata. The security impact requires prompt input from outside the operator's trust boundary; directly supplied prompt content primarily corrupts the operator's own environment. This issue is fixed in version 21.7.11.
Last activity 29 Sep 2026. Patch Forecast updates every hour.