AIKIDO-2026-307003
MessagePack is vulnerable to Deserialization of Untrusted Data
63
Medium Risk
This Affects:
MessagePackTL;DR
Typeless deserialization checks whether the outer type is disallowed, but it does not recursively inspect array element types or generic type arguments. An attacker can wrap a blocked gadget type inside an array or constructed generic so the outer name passes the policy while the inner type is still materialized. The fix applies disallow checks recursively across nested type components before formatter creation.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and use typeless deserialization on untrusted MessagePack payloads.
Background info
MessagePack is vulnerable to Deserialization of Untrusted Data 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