GHSA-9277-mp7x-85jf: dulwich (CVE-2026-42563)

Package	Ecosystem	Affected	Fixed in
dulwich	PyPI	>=0.24.0, <1.2.5	1.2.5

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Dulwich, the Python implementation of Git, versions 0.24.0 up to but not including 1.2.5 are affected. When a merge driver configured with the %P placeholder runs, a file path taken from the merged tree is passed to a shell, so an attacker who can get a victim to merge an untrusted branch with a crafted file path can run arbitrary commands. Upgrade to Dulwich 1.2.5 or later.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.7	High	4.0	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0056, the 46th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:11 UTC First seen by agentprime
31 Oct 2026, 14:11 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.