CVE-2025-68131

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/agronholm/cbor2/pull/268	Exploit Patch
https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh	Exploit Vendor Advisory
https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:agronholm:cbor2:*:*:*:*:*:python:*:*

History

02 Jan 2026, 16:40

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
First Time		Agronholm cbor2 Agronholm
References	~~() https://github.com/agronholm/cbor2/pull/268 -~~	() https://github.com/agronholm/cbor2/pull/268 - Exploit, Patch
References	~~() https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh -~~	() https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh - Exploit, Vendor Advisory
CPE		cpe:2.3:a:agronholm:cbor2::::::python::*

02 Jan 2026, 15:16

Type	Values Removed	Values Added
References	~~() https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh -~~	() https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh -

31 Dec 2025, 02:15

Type	Values Removed	Values Added
New CVE

Information

Published : 2025-12-31 02:15

Updated : 2026-01-02 16:40

NVD link : CVE-2025-68131

Mitre link : CVE-2025-68131

CVE.ORG link : CVE-2025-68131

JSON object : View

Products Affected

agronholm

cbor2

CWE

CWE-212

Improper Removal of Sensitive Information Before Storage or Transfer

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