GHSA-8QVM-5X2C-J2W7

Vulnerability from github – Published: 2025-06-16 16:02 – Updated: 2025-06-16 16:02
VLAI
Summary
protobuf-python has a potential Denial of Service issue
Details

Summary

Any project that uses Protobuf pure-Python backend to parse untrusted Protocol Buffers data containing an arbitrary number of recursive groups, recursive messages or a series of SGROUP tags can be corrupted by exceeding the Python recursion limit.

Reporter: Alexis Challande, Trail of Bits Ecosystem Security Team ecosystem@trailofbits.com

Affected versions: This issue only affects the pure-Python implementation of protobuf-python backend. This is the implementation when PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python environment variable is set or the default when protobuf is used from Bazel or pure-Python PyPi wheels. CPython PyPi wheels do not use pure-Python by default.

This is a Python variant of a previous issue affecting protobuf-java.

Severity

This is a potential Denial of Service. Parsing nested protobuf data creates unbounded recursions that can be abused by an attacker.

Proof of Concept

For reproduction details, please refer to the unit tests decoder_test.py and message_test

Remediation and Mitigation

A mitigation is available now. Please update to the latest available versions of the following packages: * protobuf-python(4.25.8, 5.29.5, 6.31.1)

Severity
8.2 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "protobuf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.25.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "protobuf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.26.0rc1"
            },
            {
              "fixed": "5.29.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "protobuf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.30.0rc1"
            },
            {
              "fixed": "6.31.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-4565"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-06-16T16:02:58Z",
    "nvd_published_at": "2025-06-16T15:15:24Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nAny project that uses Protobuf pure-Python backend to parse untrusted Protocol Buffers data containing an arbitrary number of **recursive groups**, **recursive messages** or **a series of [`SGROUP`](https://protobuf.dev/programming-guides/encoding/#groups) tags** can be corrupted by exceeding the Python recursion limit.\n\nReporter: Alexis Challande, Trail of Bits Ecosystem Security Team\n[ecosystem@trailofbits.com](mailto:ecosystem@trailofbits.com)\n\nAffected versions: This issue only affects the [pure-Python implementation](https://github.com/protocolbuffers/protobuf/tree/main/python#implementation-backends) of protobuf-python backend. This is the implementation when `PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python` environment variable is set or the default when protobuf is used from Bazel or pure-Python PyPi wheels. CPython PyPi wheels do not use pure-Python by default.\n\nThis is a Python variant of a [previous issue affecting protobuf-java](https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-735f-pc8j-v9w8).\n\n### Severity\nThis is a potential Denial of Service. Parsing nested protobuf data creates unbounded recursions that can be abused by an attacker.\n\n### Proof of Concept\nFor reproduction details, please refer to the unit tests [decoder_test.py](https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/decoder_test.py#L87-L98) and [message_test](https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/message_test.py#L1436-L1478)\n\n### Remediation and Mitigation\nA mitigation is available now. Please update to the latest available versions of the following packages:\n* protobuf-python(4.25.8, 5.29.5, 6.31.1)",
  "id": "GHSA-8qvm-5x2c-j2w7",
  "modified": "2025-06-16T16:02:58Z",
  "published": "2025-06-16T16:02:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-735f-pc8j-v9w8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-8qvm-5x2c-j2w7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4565"
    },
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/commit/17838beda2943d08b8a9d4df5b68f5f04f26d901"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/protocolbuffers/protobuf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/decoder_test.py#L87-L98"
    },
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/message_test.py#L1436-L1478"
    },
    {
      "type": "WEB",
      "url": "https://github.com/protocolbuffers/protobuf/tree/main/python#implementation-backends"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "protobuf-python has a potential Denial of Service issue"
}


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