CVE-2026-0994 PUBLISHED

Denial of Service in Python Protobuf

Assigner: Google
Reserved: 15.01.2026 Published: 23.01.2026 Updated: 23.01.2026

A denial-of-service (DoS) vulnerability exists in google.protobuf.json_format.ParseDict() in Python, where the max_recursion_depth limit can be bypassed when parsing nested google.protobuf.Any messages.

Due to missing recursion depth accounting inside the internal Any-handling logic, an attacker can supply deeply nested Any structures that bypass the intended recursion limit, eventually exhausting Python’s recursion stack and causing a RecursionError.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
CVSS Score: 8.2

Product Status

Vendor Python
Product Protobuf
Versions Default: unaffected
  • Version >= V33.0 is affected

References

Problem Types

  • CWE-674: Uncontrolled Recursion CWE

Impacts

  • CAPEC-147: XML Nested Entity Expansion