Uncontrolled Recursion Affecting protobuf package, versions [,4.25.8)[5.26.0rc1, 5.29.5)[6.30.0rc1, 6.31.1)


Severity

Recommended
0.0
high
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.06% (18th percentile)

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  • Snyk IDSNYK-PYTHON-PROTOBUF-10364902
  • published17 Jun 2025
  • disclosed16 Jun 2025
  • creditAlexis Challande

Introduced: 16 Jun 2025

NewCVE-2025-4565  (opens in a new tab)
CWE-674  (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.

CVSS Base Scores

version 4.0
version 3.1