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Low

Open Babel has out-of-bounds write (overlapping memcpy) in zipstream basic_unzip_streambuf::underflow

  • Disclosed: 30.06.2026
  • Updated: 11.10.2026 14:18

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 software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) openbabel < 3.2.0 3.2.0

References

CVSS score 7.8/10
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-787
Platform
Python (PyPI)
Package
openbabel
Disclosed
30.06.2026
Updated
11.10.2026 14:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-2776 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-8j3x-m868-cpw8 - CC BY 4.0

Vulnerability history: openbabel

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (24) in the archive
Total entries
24
First → latest
06.2026 07.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 16
  • Medium 2
  • Low 6

Disclosures per year

Severity:
  1. Open Babel has out-of-bounds write in MOPAC translationVectors[] (UNIT CELL TRANSLATION)
    High · 7.8 CVE-2022-46292 < 3.2.0 3.2.0
  2. Open Babel has out-of-bounds write in MSI translationVectors[]
    High · 7.8 CVE-2022-46295 < 3.2.0 3.2.0
  3. Open Babel has out-of-bounds write in MOPAC IN translationVectors[] (Tv atom)
    High · 7.8 CVE-2022-46294 < 3.2.0 3.2.0
  4. Open Babel has out-of-bounds write in MOPAC translationVectors[] (FINAL POINT)
    High · 7.8 CVE-2022-46293 < 3.2.0 3.2.0
  5. Open Babel has out-of-bounds write in Gaussian translationVectors[]
    High · 7.8 CVE-2022-46291 < 3.2.0 3.2.0
  6. Open Babel has out-of-bounds write in ORCA nAtoms parser (second variant)
    High · 7.8 CVE-2022-46290 < 3.2.0 3.2.0
  7. Open Babel has out-of-bounds write in ORCA nAtoms parser
    High · 7.8 CVE-2022-46289 < 3.2.0 3.2.0
  8. Open Babel has uninitialized pointer dereference in PQS pFormat
    High · 7.8 CVE-2022-46280 < 3.2.0 3.2.0
  9. Open Babel has uninitialized pointer dereference in MSI atom parser
    High · 7.8 CVE-2022-44451 < 3.2.0 3.2.0
  10. Open Babel has out-of-bounds write in MOL2 attribute/value parser
    High · 7.8 CVE-2022-43607 < 3.2.0 3.2.0
  11. Open Babel has out-of-bounds write in PQS coord_file parser
    High · 7.8 CVE-2022-43467 < 3.2.0 3.2.0
  12. Open Babel has uninitialized pointer dereference in GRO residue parser
    High · 7.8 CVE-2022-42885 < 3.2.0 3.2.0
  13. Open Babel has out-of-bounds write in CSR PadString (title field)
    High · 7.8 CVE-2022-41793 < 3.2.0 3.2.0
  14. Open Babel has out-of-bounds write in Gaussian coords_type orientation parser
    High · 7.8 CVE-2022-37331 < 3.2.0 3.2.0
  15. Open Babel has heap buffer overflow in ChemKin ChemKinFormat::CheckSpecies
    High · 7.8 CVE-2025-10997 < 3.2.0 3.2.0
  16. Open Babel has heap buffer overflow in SMILES OBSmilesParser::ParseSmiles
    High · 7.8 CVE-2025-10996 < 3.2.0 3.2.0
  17. Open Babel has out-of-bounds write (overlapping memcpy) in zipstream basic_unzip_streambuf::underflow this entry
    Low · 7.8 CVE-2025-10995 < 3.2.0 3.2.0

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