CVE-2026-122299

8.6 HIGH 0.3% exploit odds Fix listed Code execution Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-11-04 22:50 UTC ReservedThe CVE id was reserved by its CNA
2026-11-04 23:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-09 17:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 8.6 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-11-04 23:17 UTC
Last modified: 2026-11-09 17:17 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-115
Record status: Deferred

Attack profile CVSS 4.0 · 8.6

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: Active
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-122299.md and follow it. Check whether this project is affected by CVE-2026-122299. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record