CVE-2025-68131
CBORDecoder reuse can leak shareable values across decode calls
- State
- Published
- Severity
- 5.5 Medium
- Published
- Dec 31, 2025
- Updated
- Jan 2, 2026
- Reserved
- Dec 15, 2025
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.5 Medium | 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 | GitHub_M |
Weaknesses
- CWE-212 Improper Removal of Sensitive Information Before Storage or Transfer
Affected Products
| Product | Versions |
|---|---|
cbor2agronholm |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.