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.
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.