- CVE-2022-1941: ### 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](https://google.github.io/clusterfuzz/) Affected versions: All versions of C++ Protobufs (including Python) prior to the versions listed below. ### Severity & Impact As scored by google **Medium 5.7** - [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) Asscored byt NIST **High 7.5** - [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/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) - CVE-2025-4565: ### Summary 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`](https://protobuf.dev/programming-guides/encoding/#groups) tags** can be corrupted by exceeding the Python recursion limit. Reporter: Alexis Challande, Trail of Bits Ecosystem Security Team [ecosystem@trailofbits.com](mailto:ecosystem@trailofbits.com) Affected versions: This issue only affects the [pure-Python implementation](https://github.com/protocolbuffers/protobuf/tree/main/python#implementation-backends) of protobuf-python backend. This is the implementation when `PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python` environment variable is set or the default when protobuf is used from Bazel or pure-Python PyPi wheels. CPython PyPi wheels do not use pure-Python by default. This is a Python variant of a [previous issue affecting protobuf-java](https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-735f-pc8j-v9w8). ### Severity This is a potential Denial of Service. Parsing nested protobuf data creates unbounded recursions that can be abused by an attacker. ### Proof of Concept For reproduction details, please refer to the unit tests [decoder_test.py](https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/decoder_test.py#L87-L98) and [message_test](https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/message_test.py#L1436-L1478) ### Remediation and Mitigation A mitigation is available now. Please update to the latest available versions of the following packages: * protobuf-python(4.25.8, 5.29.5, 6.31.1) - CVE-2026-0994: 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.