CVE-2026-57585 HIGH

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

Vendor Msgpack
Product msgpack-python
Weakness CWE-416
Published June 30, 2026
Last update July 1, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

June 30, 2026 CVE published
July 1, 2026 Record updated