Messagepack

1 CVEs product

Monthly

CVE-2026-21452 HIGH POC PATCH This Week

MessagePack for Java versions prior to 0.9.11 are vulnerable to denial-of-service attacks through malicious .msgpack files that exploit unbounded heap allocation when deserializing EXT32 objects. An unauthenticated attacker can craft a small payload with attacker-controlled extension lengths that causes the library to attempt allocating excessive memory, leading to JVM heap exhaustion and service unavailability. Public exploit code exists for this vulnerability; organizations using affected versions should update immediately.

Java Deserialization Messagepack
NVD GitHub
CVSS 3.1
7.5
EPSS
0.0%
CVE-2026-21452
EPSS 0% CVSS 7.5
HIGH POC PATCH This Week

MessagePack for Java versions prior to 0.9.11 are vulnerable to denial-of-service attacks through malicious .msgpack files that exploit unbounded heap allocation when deserializing EXT32 objects. An unauthenticated attacker can craft a small payload with attacker-controlled extension lengths that causes the library to attempt allocating excessive memory, leading to JVM heap exhaustion and service unavailability. Public exploit code exists for this vulnerability; organizations using affected versions should update immediately.

Java Deserialization Messagepack
NVD GitHub

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