CVE-2025-4565
Python vulnerability analysis and mitigation

Overview

CVE-2025-4565 is a vulnerability in the Protobuf Pure-Python backend that affects projects parsing untrusted Protocol Buffers data. The vulnerability was disclosed on June 16, 2025, and impacts any project using the Protobuf Pure-Python backend. The issue occurs when parsing data containing an arbitrary number of recursive groups, recursive messages, or a series of SGROUP tags (NVD).

Technical details

The vulnerability stems from uncontrolled recursion when parsing Protocol Buffers data containing recursive elements. When processing untrusted data with recursive structures, the parser can exceed the Python recursion limit, leading to a RecursionError. The vulnerability has been assigned a CVSS v4.0 score of 8.2 (HIGH) with the vector string 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. The issue is classified as CWE-674 (Uncontrolled Recursion) (NVD).

Impact

When exploited, this vulnerability can result in a Denial of Service (DoS) condition by causing the application to crash with a RecursionError. This occurs when processing maliciously crafted Protocol Buffers data that contains excessive recursive structures (NVD).

Mitigation and workarounds

The recommended mitigation is to upgrade to version 6.31.1 or beyond commit 17838beda2943d08b8a9d4df5b68f5f04f26d901. The fix implements recursion depth limits in the pure Python implementation to prevent excessive recursion (NVD, GitHub Commit).

Additional resources


SourceThis report was generated using AI

Free Vulnerability Assessment

Benchmark your Cloud Security Posture

Evaluate your cloud security practices across 9 security domains to benchmark your risk level and identify gaps in your defenses.

Request assessment

Get a personalized demo

Ready to see Wiz in action?

“Best User Experience I have ever seen, provides full visibility to cloud workloads.”
David EstlickCISO
“Wiz provides a single pane of glass to see what is going on in our cloud environments.”
Adam FletcherChief Security Officer
“We know that if Wiz identifies something as critical, it actually is.”
Greg PoniatowskiHead of Threat and Vulnerability Management