# CVE-2026-57585: python-msgpack: MessagePack is the serializer implementation for Python msgpack.org

CVE-2026-57585 is fixed in python-msgpack on 1 platform, first by OPENSUSE-SU-2026:21239-1, released July 5, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-57585
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 30, 2026

## Description

MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.1, there is an Out-of-bounds read/crash on Unpacker reuse after a caught error, potentially leading to a DoS attack.  If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. This issue has been fixed in version 1.2.1.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-msgpack Debian 14 | 1.1.2-3 | [DEBIAN-CVE-2026-57585](https://patchblox.com/security/data/fix/linux/debian-cve-2026-57585.md) | Jul 7, 2026 |
| Linux | python-msgpack opensuse-leap 16.0 | 1.1.0-160000.3.1 | [OPENSUSE-SU-2026:21239-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21239-1.md) | Jul 5, 2026 |
| Linux | python-msgpack sles 15.6 | 1.0.7-150600.3.5.1 | [SUSE-SU-2026:4443-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4443-1.md) | Oct 5, 2026 |
| Linux | python-msgpack sles 15.7 | 1.0.7-150600.3.5.1 | [SUSE-SU-2026:4443-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4443-1.md) | Oct 5, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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