CVE-2026-102938

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.

CVSS 4.0

5.8CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

EPSS

0.1% chance of exploitation in the next 30 days; higher than 3% of CVEs (scores of 2026-10-25)

CWE

CWE-93

Published

2026-09-29

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

Packages (OSV)

References

• https://github.com/pypa/virtualenv/commit/a30f995461043acb6cacbf3a890951563ccf7140
• https://github.com/pypa/virtualenv/pull/3247
• https://github.com/pypa/virtualenv/releases/tag/21.7.11
• https://github.com/pypa/virtualenv/security/advisories/GHSA-9h9j-4vrj-gf7g

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