cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format. Starting in version 3.0.0 and prior to version 5.8.0, whhen a CBORDecoder instance is reused across multiple decode operations, values marked with the shareable tag (28) persist in memory and can be accessed by subsequent CBOR messages using the sharedref tag (29). This allows an attacker-controlled message to read data from previously decoded messages if the decoder is reused across trust boundaries. Version 5.8.0 patches the issue.
History

Fri, 02 Jan 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Agronholm
Agronholm cbor2
CPEs cpe:2.3:a:agronholm:cbor2:*:*:*:*:*:python:*:*
Vendors & Products Agronholm
Agronholm cbor2
Metrics cvssV3_1

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

cvssV3_1

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


Fri, 02 Jan 2026 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 01 Jan 2026 12:15:00 +0000

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:L/I:N/A:N'}

threat_severity

Moderate


Wed, 31 Dec 2025 02:00:00 +0000

Type Values Removed Values Added
Description cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format. Starting in version 3.0.0 and prior to version 5.8.0, whhen a CBORDecoder instance is reused across multiple decode operations, values marked with the shareable tag (28) persist in memory and can be accessed by subsequent CBOR messages using the sharedref tag (29). This allows an attacker-controlled message to read data from previously decoded messages if the decoder is reused across trust boundaries. Version 5.8.0 patches the issue.
Title CBORDecoder reuse can leak shareable values across decode calls
Weaknesses CWE-212
References
Metrics cvssV4_0

{'score': 5.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:P'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2025-12-31T01:15:36.827Z

Updated: 2026-01-02T14:37:55.705Z

Reserved: 2025-12-15T18:05:52.210Z

Link: CVE-2025-68131

cve-icon Vulnrichment

Updated: 2026-01-02T14:22:43.319Z

cve-icon NVD

Status : Analyzed

Published: 2025-12-31T02:15:42.527

Modified: 2026-01-02T16:40:40.337

Link: CVE-2025-68131

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-31T01:15:36Z

Links: CVE-2025-68131 - Bugzilla