Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 2.1%
CVSS Severity
CVSS v3 Score 5.4
References
Products affected by CVE-2026-54522
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cpe:2.3:a:msgpack:messagepack:0.0.1
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cpe:2.3:a:msgpack:messagepack:0.2.0
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cpe:2.3:a:msgpack:messagepack:0.2.1
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cpe:2.3:a:msgpack:messagepack:0.2.2
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cpe:2.3:a:msgpack:messagepack:0.3.0
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cpe:2.3:a:msgpack:messagepack:0.3.1
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cpe:2.3:a:msgpack:messagepack:0.3.2
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cpe:2.3:a:msgpack:messagepack:0.3.3
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cpe:2.3:a:msgpack:messagepack:0.3.4
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cpe:2.3:a:msgpack:messagepack:0.3.5
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cpe:2.3:a:msgpack:messagepack:0.3.6
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cpe:2.3:a:msgpack:messagepack:0.3.7
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cpe:2.3:a:msgpack:messagepack:0.3.8
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cpe:2.3:a:msgpack:messagepack:0.3.9
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cpe:2.3:a:msgpack:messagepack:0.4.0
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cpe:2.3:a:msgpack:messagepack:0.4.1
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cpe:2.3:a:msgpack:messagepack:0.4.2
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cpe:2.3:a:msgpack:messagepack:0.4.3
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cpe:2.3:a:msgpack:messagepack:0.4.4
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cpe:2.3:a:msgpack:messagepack:0.4.5
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cpe:2.3:a:msgpack:messagepack:0.4.6
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cpe:2.3:a:msgpack:messagepack:0.4.7
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cpe:2.3:a:msgpack:messagepack:0.4.8
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cpe:2.3:a:msgpack:messagepack:0.5.0
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cpe:2.3:a:msgpack:messagepack:0.5.1
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cpe:2.3:a:msgpack:messagepack:0.5.10
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cpe:2.3:a:msgpack:messagepack:0.5.11
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cpe:2.3:a:msgpack:messagepack:0.5.12
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cpe:2.3:a:msgpack:messagepack:0.5.2
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cpe:2.3:a:msgpack:messagepack:0.5.3
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cpe:2.3:a:msgpack:messagepack:0.5.4
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cpe:2.3:a:msgpack:messagepack:0.5.5
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cpe:2.3:a:msgpack:messagepack:0.5.6
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cpe:2.3:a:msgpack:messagepack:0.5.7
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cpe:2.3:a:msgpack:messagepack:0.5.8
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cpe:2.3:a:msgpack:messagepack:0.5.9
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cpe:2.3:a:msgpack:messagepack:0.6.0
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cpe:2.3:a:msgpack:messagepack:0.6.1
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cpe:2.3:a:msgpack:messagepack:0.6.2
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cpe:2.3:a:msgpack:messagepack:0.7.0
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cpe:2.3:a:msgpack:messagepack:0.7.1
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cpe:2.3:a:msgpack:messagepack:0.7.2
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cpe:2.3:a:msgpack:messagepack:0.7.3
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cpe:2.3:a:msgpack:messagepack:0.7.4
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cpe:2.3:a:msgpack:messagepack:0.7.5
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cpe:2.3:a:msgpack:messagepack:0.7.6
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cpe:2.3:a:msgpack:messagepack:1.0.0
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cpe:2.3:a:msgpack:messagepack:1.0.1
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cpe:2.3:a:msgpack:messagepack:1.0.2
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cpe:2.3:a:msgpack:messagepack:1.0.3
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cpe:2.3:a:msgpack:messagepack:1.1.0
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cpe:2.3:a:msgpack:messagepack:1.2.0
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cpe:2.3:a:msgpack:messagepack:1.2.1
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cpe:2.3:a:msgpack:messagepack:1.2.10
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cpe:2.3:a:msgpack:messagepack:1.2.2
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cpe:2.3:a:msgpack:messagepack:1.2.3
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cpe:2.3:a:msgpack:messagepack:1.2.4
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cpe:2.3:a:msgpack:messagepack:1.2.5
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cpe:2.3:a:msgpack:messagepack:1.2.6
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cpe:2.3:a:msgpack:messagepack:1.2.7
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cpe:2.3:a:msgpack:messagepack:1.2.8
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cpe:2.3:a:msgpack:messagepack:1.2.9
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cpe:2.3:a:msgpack:messagepack:1.3.0
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cpe:2.3:a:msgpack:messagepack:1.3.1
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cpe:2.3:a:msgpack:messagepack:1.3.2
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cpe:2.3:a:msgpack:messagepack:1.3.3
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cpe:2.3:a:msgpack:messagepack:1.4.0
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cpe:2.3:a:msgpack:messagepack:1.4.1
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cpe:2.3:a:msgpack:messagepack:1.4.2
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cpe:2.3:a:msgpack:messagepack:1.4.3
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cpe:2.3:a:msgpack:messagepack:1.4.4
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cpe:2.3:a:msgpack:messagepack:1.4.5
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cpe:2.3:a:msgpack:messagepack:1.5.0
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cpe:2.3:a:msgpack:messagepack:1.5.1
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cpe:2.3:a:msgpack:messagepack:1.5.2
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cpe:2.3:a:msgpack:messagepack:1.5.3
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cpe:2.3:a:msgpack:messagepack:1.5.4
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cpe:2.3:a:msgpack:messagepack:1.5.5
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cpe:2.3:a:msgpack:messagepack:1.5.6
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cpe:2.3:a:msgpack:messagepack:1.6.0
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cpe:2.3:a:msgpack:messagepack:1.6.1
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cpe:2.3:a:msgpack:messagepack:1.7.0
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cpe:2.3:a:msgpack:messagepack:1.7.1
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cpe:2.3:a:msgpack:messagepack:1.7.2
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cpe:2.3:a:msgpack:messagepack:1.7.3
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cpe:2.3:a:msgpack:messagepack:1.7.4
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cpe:2.3:a:msgpack:messagepack:1.7.5
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cpe:2.3:a:msgpack:messagepack:1.8.0
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cpe:2.3:a:msgpack:messagepack:1.8.1