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MEDIUM

CVE-2025-4565

CVSS v3

5.3

MEDIUM

EPSS Score

0.3 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • protobufPyPIall versions · fixed in 4.25.8

Vendor advisories

  • CVE-2025-4565 Red Hat Product Security19 products fixed · 175 known affected

    python-protobuf: Unbounded recursion in Python Protobuf

    openshift-service-mesh-dev-preview-beta/istio-ztunnel-rhel9 as a component of OpenShift Service Mesh 3 · openshift-service-mesh/istio-cni-rhel9 as a component of OpenShift Service Mesh 3 · openshift-service-mesh/istio-must-gather-rhel9 as a component of OpenShift Service Mesh 3

  • RHSA-2026:3960 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.6 Container Release Update

  • RHSA-2026:1249 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.6 Product Security and Bug Fix Update

  • RHSA-2025:10773 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.19.4 security and extras update

Full record on NVD

Description

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

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Published
2025-06-16
Last Modified
2025-08-14

Frequently asked questions

What is CVE-2025-4565?

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

Is CVE-2025-4565 actively exploited?

Active exploitation of CVE-2025-4565 has not been confirmed. Its EPSS score was 0.3% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-4565?

CVE-2025-4565 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

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Same product first, then the same vendor advisory and the same publication week.

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