CVE-2015-0838 — dulwich
CRITICALCVE-2015-0838 is a critical-severity (CVSS 9.8) Buffer Overflow vulnerability in dulwich. A fix is available for dulwich — see the affected versions and patch details below.
Dulwich Buffer Overflow when handling pack files
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
Buffer overflow in the C implementation of the apply_delta function in _pack.c in Dulwich before 0.9.9 allows remote attackers to execute arbitrary code via a crafted pack file.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | dulwich | all versions | 0.9.9pip install --upgrade 'dulwich==0.9.9' |
Affected Products
debian linuxdebiandulwichdulwich_projectDetection & 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 0.9.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-0838 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Frequently Asked Questions
Is CVE-2015-0838 in your dependencies?
Find it across PyPI, including transitive dependencies.