CVE-2026-48516

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter constructs an internal Dictionary with the default equality comparer instead of the security-aware comparer supplied by options.Security.GetEqualityComparer. This formatter omission allows...

CVE-2026-48516

MessagePack for C# (MessagePack-CSharp) prior to versions 2.5.301 and 3.1.7 constructs InterfaceLookupFormatter with a default Dictionary<TKey,IGrouping> comparer instead of the security-aware comparer from options.Security.GetEqualityComparer(). This can enable a hash-collision CPU denial-...

PT-2026-51394

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description When decompressing Lz4Block or Lz4BlockArray payloads, the software reads declared uncompressed lengths from the wire and allocates output buffer...

PT-2026-51398

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description The UnsafeBlitFormatterBase.Deserialize function reads an attacker-controlled byteLength from an extension payload and allocates an array based o...

PT-2026-51396

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description JSON conversion helpers contain multiple recursion paths that do not consistently enforce a depth limit. Specifically, the...

PT-2026-51401

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description Typeless deserialization in MessagePack-CSharp uses MessagePackSerializerOptions.ThrowIfDeserializingTypeIsDisallowedType to prevent the...

PT-2026-51399

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description Multi-dimensional array formatters read dimension lengths directly from the payload and allocate T,, T,,, or T,,, before validating that the...