CVE-2025-4565: protobuf-python — Fix

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

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CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness Type (CWE)

CWE-674 CWE-674

Affected Products

Vendor	Product	Versions
google	protobuf-python	< 4.25.8
google	protobuf-python	5.26.0 — 5.29.5
google	protobuf-python	6.30.0 — 6.31.1

References

Advisories & Patches

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

Frequently Asked Questions

What is CVE-2025-4565? +

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 It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2025-4565? +

CVE-2025-4565 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-4565? +

CVE-2025-4565 affects products from google, specifically: protobuf-python. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-4565? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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