PYSEC-2026-2776

Vulnerability from pysec - Published: 2026-07-13 15:46 - Updated: 2026-07-13 16:05
VLAI
Details

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.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
1.9 (Low)
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
Impacted products
Name purl
openbabel pkg:pypi/openbabel
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "openbabel",
        "purl": "pkg:pypi/openbabel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.8",
        "1.8.1",
        "1.8.2",
        "1.8.3",
        "1.8.4",
        "2.4.0",
        "2.4.1",
        "3.0.0",
        "3.0.0a1",
        "3.1.1",
        "3.1.1.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2025-10995",
    "GHSA-8j3x-m868-cpw8"
  ],
  "details": "### Summary\n\nA memory-safety vulnerability in Open Babel\u0027s bundled zipstream\ndecompression code caused an out-of-bounds write via overlapping\n`memcpy` when reading a crafted gzip-compressed chemistry file.\n\n### Details\n\nThe flaw was in `basic_unzip_streambuf::underflow`. The decompression\nbuffer refill path invoked `memcpy` with overlapping source and\ndestination regions, which is undefined behavior and produced\nout-of-bounds writes in practice. Any file format read through the\ngzip-wrapped reader was a potential trigger.\n\n### Impact\n\nOpen Babel is a C++ library and CLI used to read and write chemistry\nfile formats; it is shipped by Linux distributions and embedded in\nservices that may parse untrusted input. Triggering this vulnerability\nrequires the victim to open a malicious gzip-compressed chemistry file\nwith the `obabel` tool, the `OBConversion` API, or any of the language\nbindings (Python, Ruby, Java, R, Perl, C#, PHP).\n\n### Affected versions\n\nAll releases up to and including 3.1.1.\n\n### Patched version\n\n3.2.0 (released 2026-05-26).\n\n### Patch\n\nFix commit: https://github.com/openbabel/openbabel/commit/d4621d41\nOriginally reported as #2832; fixes consolidated in #2913.\n\nA minimized reproducer for this CVE is checked in under\n`test/files/fuzz_regress/` and is exercised on every CI build under\nASAN+UBSAN by the `fuzzregresstest` harness.\n\n### Credit\n\nReported via OSS-Fuzz.",
  "id": "PYSEC-2026-2776",
  "modified": "2026-07-13T16:05:17.745109Z",
  "published": "2026-07-13T15:46:25.510957Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/openbabel/openbabel/security/advisories/GHSA-8j3x-m868-cpw8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-10995"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openbabel/openbabel/issues/2832"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openbabel/openbabel/issues/2913"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openbabel/openbabel/commit/d4621d417c167b50cc8ce7aa3a02557e5b2b81c5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/openbabel/openbabel"
    },
    {
      "type": "WEB",
      "url": "https://github.com/user-attachments/files/22318572/poc.zip"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?ctiid.325923"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?id.325923"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?submit.654059"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/openbabel"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-8j3x-m868-cpw8"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Open Babel has out-of-bounds write (overlapping memcpy) in zipstream basic_unzip_streambuf::underflow"
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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