# CVE-2025-68131: cbor2: cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format

CVE-2025-68131 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2025-68131, released December 31, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-68131
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0046
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 31, 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | cbor2 Debian 14 | 5.8.0-1 | [DEBIAN-CVE-2025-68131](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68131.md) | Dec 31, 2025 |
| Linux | python-cbor2 opensuse-leap 16.0 | 5.6.5-160000.4.1 | [OPENSUSE-SU-2026:20468-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20468-1.md) | Apr 7, 2026 |
| Linux | python-cbor2 sles 16.0 | 5.6.5-160000.4.1 | [SUSE-SU-2026:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21139-1.md) | Apr 7, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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