Summary

A message parsing and memory management vulnerability in ProtocolBuffer’s C++ and Python implementations can trigger an out of memory (OOM) failure when processing a specially crafted message, which could lead to a denial of service (DoS) on services using the libraries.

Reporter: ClusterFuzz

Affected versions: All versions of C++ Protobufs (including Python) prior to the versions listed below.

Severity & Impact

Medium 5.7 - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

A small (~500 KB) malicious payload can be constructed which causes the running service to allocate more than 3GB of RAM.

Proof of Concept

For reproduction details, please refer to the unit test that identifies the specific inputs that exercise this parsing weakness.

Mitigation / Patching

Please update to the latest available versions of the following packages:

• protobuf-cpp (3.18.3, 3.19.5, 3.20.2, 3.21.6)
• protobuf-python (3.18.3, 3.19.5, 3.20.2, 4.21.6)