Affected: Open Babel

Multiple out-of-bounds write vulnerabilities exist in the translationVectors parsing functionality in multiple supported formats of Open Babel 3.1.1 and master commit 530dbfa3. A specially-crafted malformed file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.This vulnerability affects the MOPAC Cartesian file format

Affected: PyPI: openbabel

### Summary

A memory-safety vulnerability in Open Babel's MOPAC input parser allowed an out-of-bounds write into the `translationVectors[]` array when reading Tv (translation-vector) atoms from a crafted input file.

### Details

The MOPAC IN reader stored Tv-atom translation vectors into a fixed-size `translationVectors[]` array. A malformed input with more than three Tv atoms (or three plus extras) 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 input 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.