AIKIDO-2026-255937
MessagePack is vulnerable to Denial of Service (DoS)
63
Medium Risk
This Affects:
MessagePackTL;DR
When LZ4-compressed MessagePack is decompressed, declared uncompressed lengths from the wire are used to allocate output buffers before validating that the compressed data is reasonable. A small payload can claim a very large decompressed size and force large allocations or out-of-memory failures. The fix rejects negative and excessive uncompressed lengths and caps aggregate decompressed size before allocation.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and use LZ4 compression when deserializing untrusted MessagePack payloads.
Background info
MessagePack is vulnerable to Denial of Service (DoS) in versions 0.0.1 - 2.5.300 and 3.0.0 - 3.1.6.
How to fix this
Upgrade the MessagePack library to the patch version.
Are You Affected?
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SOC 2Compliant
ISO 27001Compliant