AIKIDO-2026-845611
MessagePack is vulnerable to Denial of Service (DoS)
63
Medium Risk
This Affects:
MessagePackTL;DR
Runtime-generated union deserializers from DynamicUnionResolver do not call MessagePackSecurity.DepthStep around recursive deserialization or reader.Skip on unknown union keys. Untrusted union payloads can bypass configured object graph depth limits and recurse until the process crashes with an uncatchable StackOverflowException. The fix emits depth-step and cleanup IL in generated union deserializers consistent with other recursive formatters.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and deserialize untrusted payloads into Union-decorated types handled by DynamicUnionResolver.
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?
Connect your repositories to instantly see whether vulnerable or malicious packages exist in your codebase.
Free. No credit card required.
SOC 2Compliant
ISO 27001Compliant