---
id: CVE-2025-10995
title: >-
  Open Babel has out-of-bounds write (overlapping memcpy) in zipstream
  basic_unzip_streambuf::underflow
summary: >-
  Open Babel has out-of-bounds write (overlapping memcpy) in zipstream
  basic_unzip_streambuf::underflow
severity: low
cvss: 7.8
cwe:
  - CWE-787
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-8j3x-m868-cpw8'
references:
  - url: >-
      https://github.com/openbabel/openbabel/security/advisories/GHSA-8j3x-m868-cpw8
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-10995'
  - url: 'https://github.com/openbabel/openbabel/issues/2832'
  - url: 'https://github.com/openbabel/openbabel/issues/2913'
  - url: >-
      https://github.com/openbabel/openbabel/commit/d4621d417c167b50cc8ce7aa3a02557e5b2b81c5
  - url: 'https://github.com/user-attachments/files/22318572/poc.zip'
  - url: 'https://vuldb.com/?ctiid.325923'
  - url: 'https://vuldb.com/?id.325923'
  - url: 'https://vuldb.com/?submit.654059'
  - url: 'https://github.com/advisories/GHSA-8j3x-m868-cpw8'
tags:
  - ghsa
  - pip
epss: 0.00252
epssPercentile: 0.14899
ingestedAt: '2026-06-30T21:50:09.516Z'
---

## Overview

### Summary

A memory-safety vulnerability in Open Babel's bundled zipstream
decompression code caused an out-of-bounds write via overlapping
`memcpy` when reading a crafted gzip-compressed chemistry file.

### Details

The flaw was in `basic_unzip_streambuf::underflow`. The decompression
buffer refill path invoked `memcpy` with overlapping source and
destination regions, which is undefined behavior and produced
out-of-bounds writes in practice. Any file format read through the
gzip-wrapped reader was a potential trigger.

### 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 gzip-compressed chemistry 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/d4621d41
Originally reported as #2832; 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`