CVE-2025-4565

Unbounded recursion in Python Protobuf

Published Jun 16, 2025 CVSS 4.0 · 8.2 High EPSS < 1% KEV · Not listed
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

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-18401 protobuf-python has a potential Denial of Service issue
Github GHSA Github GHSA GHSA-8qvm-5x2c-j2w7 protobuf-python has a potential Denial of Service issue
Ubuntu USN Ubuntu USN USN-7629-1 Protocol Buffers vulnerabilities
Ubuntu USN Ubuntu USN USN-7629-2 Protocol Buffers vulnerabilities
History
Type Values Removed Values Added
First Time appeared Google protobuf-python
CPEs cpe:2.3:a:google:protobuf:4.25.8:*:*:*:*:python:*:*
cpe:2.3:a:google:protobuf:5.29.5:*:*:*:*:python:*:*
cpe:2.3:a:google:protobuf:6.31.1:*:*:*:*:python:*:*
cpe:2.3:a:google:protobuf-python:*:*:*:*:*:*:*:*
Vendors & Products Google protobuf
Google protobuf-python
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Type Values Removed Values Added
First Time appeared Google
Google protobuf
CPEs cpe:2.3:a:google:protobuf:4.25.8:*:*:*:*:python:*:*
cpe:2.3:a:google:protobuf:5.29.5:*:*:*:*:python:*:*
cpe:2.3:a:google:protobuf:6.31.1:*:*:*:*:python:*:*
Vendors & Products Google
Google protobuf
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Moderate

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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
Title Unbounded recursion in Python Protobuf
Weaknesses CWE-674
References
Metrics cvssV4_0

{'score': 8.2, '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:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Google
Published
Updated
Jun 16, 2025, 3:39 PM
Reserved
May 12, 2025, 5:48 AM
Status
Analyzed
Published
Jun 16, 2025, 3:15 PM
Modified
Jun 17, 2026, 9:33 AM
Severity
Moderate
Public date
Jun 16, 2025, 2:50 PM