vulnerability / NVI-00013060 / Revision 1
Dulwich: Symlink directory traversal in stash pop allows arbitrary file write via intermediate directory symlinks
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.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.6 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
dulwich
source listed>= 0.22.5, <= 1.2.7
## Summary Dulwich's `stash.py:pop()` function is vulnerable to symlink directory traversal, allowing an attacker to write arbitrary files outside the repository worktree when a victim pops a stash in a malicious repository. ## Root Cause The `pop()` function at `dulwich/stash.py:236` uses `os.path.exists(parent_dir)` to check if a parent directory exists before writing stashed files. `os.path.exists()` follows symlinks, so when an intermediate directory in the path is a symlink pointing outside the worktree (e.g., `link → ../../.git/hooks`), the check passes and subsequent file writes resolve through the symlink. The `validate_path()` function (line 228) only validates path component names against `INVALID_DOTNAMES` — it performs zero filesystem symlink detection. On dulwich 1.2.7 (latest release), `build_file_from_blob()` has no symlink protection whatsoever. ## Impact An attacker can craft a malicious repository that, when a victim clones it and performs a stash pop operation, writes attacker-controlled content to arbitrary filesystem locations. Writing to `.git/hooks/post-checkout` achieves Remote Code Execution on the victim's machine on the next git checkout operation.
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-cm62-gvxx-vmxx ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.