CVE-2025-4565

Unbounded recursion in Python Protobuf

State: Published
Severity: 8.2 High
Published: Jun 16, 2025
Updated: Jun 16, 2025
Reserved: May 12, 2025

Description

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. This can result in a Denial of service by crashing the application with a RecursionError. We recommend upgrading to version =>6.31.1 or beyond commit 17838beda2943d08b8a9d4df5b68f5f04f26d901

Scores

CVSS	Score	Vector	Source
4.0	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	Google

Weaknesses

CWE-674 Uncontrolled Recursion

Affected Products

Product	Versions
Python-Protobufprotocolbuffers	before 4.25.8Affected before 5.29.5Affected before 6.31.1Affected
Python-Protobufprotocolbuffers	before 4.25.8Affected before 5.29.5Affected before 6.31.1Affected

References

https://github.com/protocolbuffers/protobuf/commit/17838beda2943d08b8a9d4df5b68f5f04f26d901

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