How severe is CVE-2026-114097?

No CVSS score has been assigned to CVE-2026-114097 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-114097?

CVE-2026-114097 affects the following packages: dulwich (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-114097?

Update dulwich to 1.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-114097 is resolved across your whole dependency graph.

How do I detect CVE-2026-114097 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dulwich, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-114097 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2026-114097 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-114097 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-114097?

CVE-2026-114097 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 4th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-114097?

CVE-2026-114097 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-114097 published, and has it been updated?

CVE-2026-114097 was published on October 21, 2026 and was last updated on October 23, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-114097 — dulwich

Fix: jelmer/dulwich@9571ac6

CVE-2026-114097 is a Path Traversal vulnerability in dulwich. A fix is available for dulwich — see the affected versions and patch details below.

Dulwich 0.23.1 before 1.2.8 Symlink Path Traversal via filter_branch Index Filter

Also known asGHSA-5fqc-mrg8-w798

Published

Oct 21, 2026

Updated

Oct 23, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-114097.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs4th percentile — riskier than 4% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍dulwich

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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() 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.

On dulwich 1.2.7, build_file_from_blob() has no symlink protection, and validate_path_element only validates name patterns, not filesystem state.

Impact

An attacker can craft a malicious repository where running filter_branch with an index filter writes attacker-controlled content to arbitrary filesystem locations via symlink traversal. This achieves RCE if the write targets .git/hooks/.

Attack Scenario

Attacker creates a repository where commit history (linearized) has:
- Ancestor commit: tree entry evil (mode 120000, symlink → /target_dir)
- Descendant commit: tree entry evil/payload (mode 100644, attacker content)
Victim clones repository and runs filter_branch with an index filter
process_commit() processes ancestor first → materializes evil as symlink to /target_dir in CWD
CWD is NOT cleaned between commits
Processing descendant: os.path.exists("./evil") → True (symlink exists). build_file_from_blob(blob, mode, "./evil/payload") → open("./evil/payload", "wb") follows intermediate symlink → writes to /target_dir/payload

Suggested Fix

Clean the CWD between commit iterations in _apply_index_filter(), or verify that no intermediate path components are symlinks before writing files.

Reported by zx (Jace)

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`dulwich`	≥ 0.23.1&&< 1.2.8	1.2.8`pip install --upgrade 'dulwich==1.2.8'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dulwich, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update dulwich to 1.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-114097 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

## 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()` 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

O3 Security · Impact-Aware SCA

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