CVE-2025-4565

low-risk
Published 2025-06-16

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

Do I need to act?

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0.02% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.3/10 Medium
NETWORK / LOW complexity

Affected Products (1)

Protobuf-Python

Affected Vendors

26
/ 100
low-risk
Severity 21/34 · High
Exploitability 0/34 · Minimal
Exposure 5/34 · Minimal