{"items":[{"id":"NVI-00012934","kind":"vulnerability","title":"Dulwich: Symlink directory traversal in filter-branch index_filter via cross-commit state persistence","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-5fqc-mrg8-w798"],"plain_summary":"GitHub lists this reviewed advisory for dulwich. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-12a5f13e5a0b521e7b5e65a3962e97a6"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-02T18:53:05.000Z","value":"8.6 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-12a5f13e5a0b521e7b5e65a3962e97a6"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-12a5f13e5a0b521e7b5e65a3962e97a6","url":"https://github.com/advisories/GHSA-5fqc-mrg8-w798","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-5fqc-mrg8-w798","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T01:40:00.567Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-12a5f13e5a0b521e7b5e65a3962e97a6"],"technology":"dulwich","known_exclusions":[],"conditions_summary":"## Summary\n\nDulwich'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.\n\n## Root Cause\n\n`_apply_index_filter()` at `dulwich/filter_branch.py:212` calls `build_index_from_tree(\".\", tmp_index_path, ...)` which materializes all tree entries to the current working directory. The `finally` block (line 229-230) only cleans up the temporary index file (`os.unlink(tmp_index_path)`) — NOT the filesystem files written to CWD. When `process_commit()` processes parents recursively first (line 260), files materialized from ancestor commits persist and affect processing of descendant commits.\n\nOn dulwich 1.2.7, `build_file_from_blob()` has no symlink protection, and `validate_path_element` only validates name patterns, not filesystem state.\n\n## Impact\n\nAn attacker can craft a malicious repository where running `filter_branch` with an index filter writes attacker-controlled content to arbitrary","public_affected_ranges":[">= 0.23.1, <= 1.2.7"]}],"null_published_at":"2026-11-01T07:29:12.903Z","source_updated_at":"2026-10-02T18:53:05.000Z","source_disclosed_at":"2026-10-02T18:53:05.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-01T01:40:00.567Z"}],"next_cursor":null,"snapshot_revision":"42594"}