CVE-2026-122299
Description
A flaw was found in Dulwich. This flaw allows arbitrary code execution on systems that process untrusted repositories. When parsing Git commit objects, Dulwich resolves duplicate tree headers to the last occurrence instead of the first, conflicting with standard Git behavior. A remote attacker can exploit this issue by crafting a commit with multiple tree headers, causing applications that rely on Dulwich to check out malicious code while standard Git review and continuous integration (CI) systems display benign files.
Statement
This vulnerability is rated as an Important severity risk because successful exploitation can result in full code execution on build systems or developer workstations, though it requires tricking a user or pipeline into processing an untrusted Git dependency. In typical Red Hat deployments, Dulwich is not run as an exposed network service, but rather operates within development environments or packaging toolchains to handle repository operations. Because Dulwich resolves duplicated tree definitions differently from reference Git implementations, malicious payloads can bypass standard code review or CI audit checks, making this a high-impact supply chain concern.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Unexpected State
Frequently Asked Questions
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