A memory-safety vulnerability in Open Babel's CDXML file format parser caused a NULL pointer dereference when reading a crafted input file.
The flaw was in OBAtom::GetExplicitValence as called from the CDXML
parser. A malformed fragment caused the parser to invoke the method
on a NULL atom pointer.
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 CDXML file with the obabel
tool, the OBConversion API, or any of the language bindings (Python,
Ruby, Java, R, Perl, C#, PHP).
All releases up to and including 3.1.1.
3.2.0 (released 2026-05-26).
Fix commit: https://github.com/openbabel/openbabel/commit/e23a224b Tracked in #2862.
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.
Reported by Vedant Madane (@VedantMadane) via VulDB.
{
"cwe_ids": [
"CWE-476"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-30T18:47:28Z",
"nvd_published_at": null,
"severity": "LOW"
}