---
id: CVE-2025-10996
title: 'Open Babel has heap buffer overflow in SMILES OBSmilesParser::ParseSmiles'
summary: 'Open Babel has heap buffer overflow in SMILES OBSmilesParser::ParseSmiles'
severity: high
cvss: 7.8
cwe:
  - CWE-119
vendor: openbabel
product: openbabel
ecosystem: pip
affected:
  - openbabel < 3.2.0
patched:
  - openbabel 3.2.0
published: '2026-06-30'
updated: '2026-06-30'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-j35x-w4gj-pf7w'
references:
  - url: >-
      https://github.com/openbabel/openbabel/security/advisories/GHSA-j35x-w4gj-pf7w
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-10996'
  - url: 'https://github.com/openbabel/openbabel/issues/2831'
  - url: 'https://github.com/openbabel/openbabel/pull/2913'
  - url: 'https://github.com/openbabel/openbabel/commit/b34cd604'
  - url: 'https://github.com/user-attachments/files/22318556/poc.zip'
  - url: 'https://vuldb.com/?ctiid.325924'
  - url: 'https://vuldb.com/?id.325924'
  - url: 'https://vuldb.com/?submit.654060'
  - url: 'https://github.com/advisories/GHSA-j35x-w4gj-pf7w'
tags:
  - ghsa
  - pip
epss: 0.0028
epssPercentile: 0.18225
ingestedAt: '2026-06-30T21:50:09.513Z'
---

## Overview

### Summary

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.

### 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/b34cd604
Originally reported as #2831; fixes consolidated in #2913.

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 via OSS-Fuzz.

## Affected packages

- `openbabel < 3.2.0`

## Remediation

Upgrade to a patched release:

- `openbabel 3.2.0`