CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Buffer#clear in ext/msgpack/buffer.c leaves rmem_last, rmem_end, and rmem_owner stale after _msgpack_buffer_shift_chunk returns an rmem page to the shared pool, allowing a subsequent Buffer#write and a second MessagePack::Buffer to alias the page and disclose or corrupt cross-buffer data. This issue is fixed in version 1.8.2.

CVSS v3 5.4 MEDIUM

5.4^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90	Patch
https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938	Exploit Vendor Advisory
https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:ruby:*:*

History

No history.

Information

Published : 2026-07-30 17:16

Updated : 2026-08-05 19:41

NVD link : CVE-2026-54522

Mitre link : CVE-2026-54522

CVE.ORG link : CVE-2026-54522

JSON object : View

Products Affected

msgpack

messagepack

CWE

CWE-416

Use After Free

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