A vulnerability was detected in Open Babel up to 3.1.1. The impacted element is the function OBAtom::SetFormalCharge in the library include/openbabel/atom.h of the component MOL2 File Handler. The manipulation results in out-of-bounds read. It is possible to launch the attack remotely. The exploit is now public and may be used. The patch is identified as e23a224b8fd9d7c2a7cde9ef4ec6afb4c05aa08a. A patch should be applied to remediate this issue. The project was informed of the problem early through an issue report but has not responded yet.

Affected: PyPI: openbabel

### Summary

A memory-safety vulnerability in Open Babel's MOL2 file format parser caused a NULL pointer dereference when reading a crafted input file.

### Details

The flaw was in `OBAtom::SetFormalCharge` as called from the MOL2 parser. A malformed atom record caused the parser to call the method on a NULL atom pointer.

### 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 MOL2 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/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.

### Credit

Reported by Vedant Madane (@VedantMadane) via VulDB.

libopenbabel8-3.2.0-1.1 on GA media

Affected: PyPI: openbabel

### Summary

A memory-safety vulnerability in Open Babel's MOL2 file format parser caused a NULL pointer dereference when reading a crafted input file.

### Details

The flaw was in `OBAtom::SetFormalCharge` as called from the MOL2 parser. A malformed atom record caused the parser to call the method on a NULL atom pointer.

### 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 MOL2 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/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.

### Credit

Reported by Vedant Madane (@VedantMadane) via VulDB.

Affected: Ubuntu:16.04:LTS: openbabel, Ubuntu:18.04:LTS: openbabel, Ubuntu:20.04:LTS: openbabel, Ubuntu:22.04:LTS: openbabel, Ubuntu:24.04:LTS: openbabel, Ubuntu:25.10: openbabel, Ubuntu:26.04:LTS: openbabel

A vulnerability was detected in Open Babel up to 3.1.1. The impacted element is the function OBAtom::SetFormalCharge in the library include/openbabel/atom.h of the component MOL2 File Handler. The manipulation results in out-of-bounds read. It is possible to launch the attack remotely. The exploit is now public and may be used. The patch is identified as e23a224b8fd9d7c2a7cde9ef4ec6afb4c05aa08a. A patch should be applied to remediate this issue. The project was informed of the problem early through an issue report but has not responded yet.