GHSA-55f6-pf8r-c2f4: Open Babel has out-of-bounds write in MOPAC translationVectors[] (UNIT CELL TRANSLATION)

Summary 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. Details 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. 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 MOPAC output 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/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. Credit Reported by Cisco TALOS.