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TI-2026-85266 Aliases CVE-2026-122299GHSA-6jv4-m4h7-2vv8

Dulwich commit parser picks the wrong tree from duplicate headers

Priority LOW 37CWE-115Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

Dulwich before 1.2.20 mishandles commit objects that contain two tree headers. Its commit parser resolves a duplicate tree header to the last occurrence instead of the first, which differs from core git (CWE-115). An attacker with no privileges can craft a commit so that reviewers using git see a benign tree, while Poetry 2.5.1, which uses dulwich by default for git dependencies, checks out an attacker-controlled tree containing build scripts such as setup.py. This leads to code execution on the install or build host.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

EPSS 0.00325 25th percentileScored 2026-11-07
Fix Partial dulwich (jelmer): 1.2.20Red Hat: 5 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
jelmerdulwichbefore 1.2.201.2.20Patch availableCNA
  • dulwich Vendorjelmer Affected before 1.2.20 Fixed in 1.2.20 Patch available CNA

Remediation

Upgrade Dulwich to 1.2.20 or later, the fixed version. Red Hat lists Red Hat Ansible Automation Platform 2, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift AI (RHOAI) and Red Hat OpenShift Container Platform 4 as affected without a fix.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA dulwich (jelmer) Fixed in 1.2.20

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Ansible Automation Platform 2Affected—
Red Hat Enterprise Linux 7Affected—
Red Hat Enterprise Linux 8Affected—
Red Hat OpenShift AI (RHOAI)Affected—
Red Hat OpenShift Container Platform 4Affected—

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-122299
  2. 2026-11-05 Alias added: GHSA-6jv4-m4h7-2vv8
  3. 2026-11-06 Priority changed: MEDIUM → LOW
  4. 2026-11-06 Affected versions changed · Red Hat
  5. 2026-11-06 CVSS score added · Red Hat

References

Patch 1

Other 1

  • TI-2026-78707 Path traversal in Dulwich lets attackers write files on Windows CVSS 4.0HIGH 8.7
  • TI-2026-37846 Path traversal in jelmer dulwich CVSS 3.1HIGH 7.5
  • TI-2026-30843 Dulwich Vulnerable to Command Injection via Merge Driver Path CVSS 4.0HIGH 7.7
  • TI-2026-78709 Symlink following in Dulwich checkout allows arbitrary file writes CVSS 4.0HIGH 7.3
  • TI-2026-30613 Dulwich has an arbitrary file write via NTFS-hostile tree entries on Windows CVSS 3.1HIGH 8.8
  • TI-2026-78708 Infinite recursion in Dulwich pack parsing causes denial of service CVSS 4.0HIGH 7.1
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences