Intel

AIKIDO-2026-856904

MessagePack is vulnerable to Denial of Service (DoS)

Denial of Service (DoS)CVE-2026-48515 Published Yesterday

63

Medium Risk

This Affects:

DOTNETMessagePack
0.0.1 - 2.5.300
Fixed in 2.5.301
3.0.0 - 3.1.6
Fixed in 3.1.7
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TL;DR

Multi-dimensional array formatters read dimension lengths from the payload and allocate T[,], T[,,], or T[,,,] before confirming that the dimension product matches the encoded element count. A small payload can declare huge dimensions with a tiny inner array and force large heap allocations or out-of-memory failures. The fix validates non-negative dimensions and their checked product against the element count before allocation.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and deserialize untrusted payloads into multi-dimensional array types.

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.