CVE-2026-57585
Published:June 30, 2026
Updated:August 04, 2026
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.
Affected Packages
msgpack (CONDA):
Affected version(s) =0.2.3 <1.2.1Fix Suggestion:
Update to version 1.2.1msgpack-python (CONDA):
Affected version(s) >=0.4.6 <1.2.1Fix Suggestion:
Update to version 1.2.1https://github.com/msgpack/msgpack-python.git (GITHUB):
Affected version(s) >=v0.6.0 <v1.2.1Fix Suggestion:
Update to version v1.2.1msgpack (PYTHON):
Affected version(s) >=0.5.0 <1.2.1Fix Suggestion:
Update to version 1.2.1msgpack-python (PYTHON):
Affected version(s) >=0.1.2 <1.2.1Fix Suggestion:
Update to version 1.2.1Related Resources (6)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Use After Free
EPSS
Base Score:
0.28