GHSA-8j3x-m868-cpw8 is a high-severity (CVSS 7.8) Buffer Overflow vulnerability in openbabel. O3 Security confirms whether GHSA-8j3x-m868-cpw8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Open Babel has out-of-bounds write (overlapping memcpy) in zipstream basic_unzip_streambuf::underflow
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.
Exploitation and automatability from CISA’s SSVC triage for GHSA-8j3x-m868-cpw8.
Real-World Exposure
openbabelReal-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
A memory-safety vulnerability in Open Babel's bundled zipstream
decompression code caused an out-of-bounds write via overlapping
memcpy when reading a crafted gzip-compressed chemistry file.
Details
The flaw was in basic_unzip_streambuf::underflow. The decompression
buffer refill path invoked memcpy with overlapping source and
destination regions, which is undefined behavior and produced
out-of-bounds writes in practice. Any file format read through the
gzip-wrapped reader was a potential trigger.
Impact
Open Babel is a C++ library and CLI used to read and write chemistry
file formats; it is shipped by Linux distributions and embedded in
services that may parse untrusted input. Triggering this vulnerability
requires the victim to open a malicious gzip-compressed chemistry file
with the obabel tool, the OBConversion API, or any of the language
bindings (Python, Ruby, Java, R, Perl, C#, PHP).
Affected versions
All releases up to and including 3.1.1.
Patched version
3.2.0 (released 2026-05-26).
Patch
Fix commit: https://github.com/openbabel/openbabel/commit/d4621d41 Originally reported as #2832; fixes consolidated in #2913.
A minimized reproducer for this CVE is checked in under
test/files/fuzz_regress/ and is exercised on every CI build under
ASAN+UBSAN by the fuzzregresstest harness.
Credit
Reported via OSS-Fuzz.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | openbabel | all versions | 3.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openbabel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update openbabel to 3.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8j3x-m868-cpw8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-8j3x-m868-cpw8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-8j3x-m868-cpw8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-8j3x-m868-cpw8 in your dependencies?
O3 detects GHSA-8j3x-m868-cpw8 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.