CVE-2026-57585

HIGH

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

Title source: cna
STIX 2.1

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.

References (2)

Core 2

Scores

CVSS v3 7.5
EPSS 0.0028
EPSS Percentile 19.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-416
Status published
Products (1)
msgpack/msgpack-python < 1.2.1
Published Jun 30, 2026
Tracked Since Jul 01, 2026