Dulwich: Symlink directory traversal in filter-branch index_filter via cross-commit state persistence — GHSA-5FQC-MRG8-W798

Summary

## Summary Dulwich's `filter_branch.py` `CommitFilter._apply_index_filter()` is vulnerable to symlink directory traversal. When processing commit history, materialized tree entries (including symlinks) persist in the working directory between commits, allowing a symlink from an ancestor commit to redirect file writes from a descendant commit to arbitrary filesystem locations. ## Root Cause `_apply_index_filter()`…

Timeline

Published by source

2026-10-02

Risk context

• Reported severity or threat level: high.
• Reported CVSS score: 8.6 out of 10.
• Review exposure for the affected product or family: pip: dulwich.

Product

pip: dulwich

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source

Evidence and provenance

Canonical advisory ID

GHSA-5FQC-MRG8-W798

Source

GitHub

Vendor

GitHub

Published by source

2026-10-02

Last source activity

2026-10-02

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.