CVE-2026-54522

LOW CVSS 4.0: 2.1 EPSS 0.14%
Updated Aug 05, 2026
Msgpack
Parameter Value
CVSS 2.1 (LOW)
Affected Versions before 1.8.2
Fixed In 1.8.2
Type CWE-416 (Use After Free)
Vendor Msgpack
Public PoC No

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.

Attack Parameters

Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Msgpack Messagepack
cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:ruby:*:*
1.8.2

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