CVE-2026-57585

HIGH CVSS 3.1: 7.5 EPSS 0.28%
Updated Aug 06, 2026
Msgpack
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions before 1.2.1
Fixed In 1.2.1
Type CWE-416 (Use After Free)
Vendor Msgpack
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Msgpack Messagepack
cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:python:*:*
1.2.1

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