GHSA-j35x-w4gj-pf7w is a high-severity (CVSS 7.8) Buffer Overflow vulnerability in openbabel. A fix is available for openbabel — see the affected versions and patch details below.
Open Babel has heap buffer overflow in SMILES OBSmilesParser::ParseSmiles
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-j35x-w4gj-pf7w.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-j35x-w4gj-pf7w by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 247,569 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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 SMILES parser caused a heap buffer overflow when reading a crafted input string.
Details
The flaw was in OBSmilesParser::ParseSmiles. A malformed SMILES
input caused the parser to write past the end of a heap-allocated
buffer.
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 parse a malicious SMILES string with the
obabel tool, the OBConversion API, or any of the language
bindings (Python, Ruby, Java, R, Perl, C#, PHP). SMILES strings are
commonly passed on the command line and through scripted pipelines,
so this primitive is especially reachable.
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/b34cd604 Originally reported as #2831; 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 | 3.2.0pip install --upgrade 'openbabel==3.2.0' |
Affected Products
open babelopenbabelDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openbabel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openbabel to 3.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j35x-w4gj-pf7w is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Frequently Asked Questions
Is GHSA-j35x-w4gj-pf7w in your dependencies?
Find it across PyPI, including transitive dependencies.