PYSEC-2026-899

    Dashboard / Vulnerabilities / PYSEC-2026-899

    PYSEC-2026-899

    Published: 7 Jul 2026Last Modified: 7 Jul 2026

    Summary: protobuf-cpp and protobuf-python have potential Denial of Service issue

    Details: ### 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)

    References: https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-8gq9-2x98-w8hf, https://nvd.nist.gov/vuln/detail/CVE-2022-1941, https://cloud.google.com/support/bulletins#GCP-2022-019, https://github.com/protocolbuffers/protobuf, https://lists.debian.org/debian-lts-announce/2023/04/msg00019.html, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CBAUKJQL6O4TIWYBENORSY5P43TVB4M3, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MPCGUT3T5L6C3IDWUPSUO22QDCGQKTOP, https://lists.fedoraproject.org/archives/list/[email protected]/message/CBAUKJQL6O4TIWYBENORSY5P43TVB4M3, https://lists.fedoraproject.org/archives/list/[email protected]/message/MPCGUT3T5L6C3IDWUPSUO22QDCGQKTOP, https://security.netapp.com/advisory/ntap-20240705-0001, http://www.openwall.com/lists/oss-security/2022/09/27/1, https://pypi.org/project/protobuf, https://github.com/advisories/GHSA-8gq9-2x98-w8hf

    Affected packages

    Package

    Name: protobuf

    Purl: pkg:pypi/protobuf

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.18.3

    Affected versions

    2.0.0beta
    2.0.3

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    PYSEC-2026-899 | CVE-DB