High 7.5Published Jun 30, 2026

CVE-2026-57585MessagePack: Out-of-bounds read/crash on Unpacker reuse after caught error

Updated under an hour ago (Oct 27, 2026, 10:30 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for msgpack-python

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

msgpack msgpack-python msgpack:python (from the name)	before 1.2.1	CNA record
msgpack messagepack msgpack:messagepack	before 1.2.1	NVD

References

References

https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964	x-refsource-confirm, mitigation, vendor-advisory
https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476d	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.