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CVE-2026-48513

MessagePack-CSharp: DynamicUnionResolver generated deserializers miss depth enforcement PUBLISHED

Description (CNA)

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, runtime-generated union deserializers emitted by DynamicUnionResolver do not call MessagePackSecurity.DepthStep(ref reader) and do not decrement reader.Depth around recursive deserialization and skip paths. This means union deserialization does not consistently participate in the maximum object graph depth enforcement that protects other recursive formatter paths. For unknown union keys, the emitted deserializer calls reader.Skip() on attacker-controlled data without an enclosing depth step. This vulnerability is fixed in 2.5.301 and 3.1.7.

Affected (CNA)

Vendor / productVersions
MessagePack-CSharp / MessagePack-CSharpaffected >= 3.0, < 3.1.7; affected < 2.5.301

CWE

CWE-674

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.