Uncontrolled Recursion Affecting protobuf package, versions [,4.25.8)[5.26.0rc1, 5.29.5)[6.30.0rc1, 6.31.1)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-PROTOBUF-10364902
- published17 Jun 2025
- disclosed16 Jun 2025
- creditAlexis Challande
Introduced: 16 Jun 2025
CVE-2025-4565 (opens in a new tab)How to fix?
Upgrade protobuf to version 4.25.8, 5.29.5, 6.31.1 or higher.
Overview
protobuf is a Google’s data interchange format
Affected versions of this package are vulnerable to Uncontrolled Recursion when parsing untrusted Protocol Buffers data containing an excessive number of recursive groups, recursive messages, or a series of SGROUP tags. An attacker can provide crafted input that will corrupt the backend by exceeding the Python recursion limit and result in denial of service by crashing the application with a RecursionError.
Note: This problem impacts only the pure-Python implementation of the protobuf-python backend and does not influence the CPython PyPi wheels, which, by default, do not utilize pure Python.