A memory-safety vulnerability in Open Babel's MOPAC output parser
allowed an out-of-bounds write into the translationVectors[] array
when reading the "UNIT CELL TRANSLATION" block of a crafted input
file.
The MOPAC output reader stored translation vectors from the UNIT CELL
TRANSLATION block into a fixed-size translationVectors[] array. A
malformed block could push more vectors than the array had slots,
causing a write past the end of the array. One of five
translationVectors[] OOB writes in the TALOS 2022 batch.
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 MOPAC output 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/40e85213
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 Cisco TALOS.
3.2.0Exploitability
AV:LAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:H7.8/CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H