CVE-2026-122299 Dulwich before 1.2.20 Commit Parser Tree Header Misinterpretation
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-122299?
CVE-2026-122299 is a high-severity vulnerability in jelmer dulwich, published on 4 Nov 2026.
Official description
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
Which versions are affected by CVE-2026-122299?
How do I fix CVE-2026-122299?
No fix has been published for CVE-2026-122299 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-122299 being exploited?
There is no known exploitation of CVE-2026-122299 in the wild and no public exploit code.
Sources
Also known as AZL-112720, DEBIAN-CVE-2026-122299, GHSA-6jv4-m4h7-2vv8, UBUNTU-CVE-2026-122299.