CVE-2017-17458: Debian Linux

Critical severity, CVSS 9.8. EPSS: 6.3% chance of exploitation in the next 30 days.

In Mercurial before 4.4.1, it is possible that a specially malformed repository can cause Git subrepositories to run arbitrary code in the form of a .git/hooks/post-update script checked into the repository. Typical use of Mercurial prevents construction of such repositories, but they can be created programmatically.

Affected products

• Debian Debian Linux: version 7.0 only; version 8.0 only
• Mercurial Mercurial: before 4.4.1 (fixed in 4.4.1)

Published 2017-12-07. Last modified 2026-06-17.