EUVD-2026-38381

MessagePack-CSharp: Multi-dimensional array formatters allocate from unchecked dimensions...

EUVD-2026-38385

MessagePack-CSharp: ExpandoObject formatter can perform quadratic insertion work on untrusted maps...

CVE-2026-48514

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, UnsafeBlitFormatterBase.Deserialize reads an attacker-controlled byteLength from an extension payload and allocates an array based on that value before validating it against the extension header length or remaining...

CVE-2026-48517

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's typeless deserialization includes MessagePackSerializerOptions.ThrowIfDeserializingTypeIsDisallowedType as a safety check for dangerous types. The default implementation checks the outer type nam...

CVE-2026-48502

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePackReader.ReadDateTime can allocate stack memory based on an attacker-controlled MessagePack extension length. In the slow path for timestamp extension parsing, the computed tokenSize includes the extension...

CVE-2026-48509

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, the parameterless MessagePackInputFormatter constructor uses default serializer options, which resolve to MessagePackSerializerOptions.Standard with MessagePackSecurity.TrustedData. The formatter is designed for...

CVE-2026-48512

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's JSON conversion helpers contain multiple recursion paths that do not consistently enforce a depth limit. These paths are in the JSON conversion component rather than normal typed MessagePack...

CVE-2026-48109

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, A vulnerability exists in the optional LZ4 decompression path used by MessagePack compression modes Lz4Block and Lz4BlockArray. The decoder implementation is based on a deprecated fast-decompression algorithm that do...

CVE-2026-48502

MessagePack-CSharp contains a Denial of Service vulnerability in MessagePackReader.ReadDateTime() where a stack allocation is driven by attacker-controlled extension length. In the slow path, tokenSize includes the extension body length and is used in a stackalloc before the extension length is v...

CVE-2026-48509 MessagePack-CSharp: ASP.NET Core MessagePackInputFormatter defaults to TrustedData for HTTP request bodies

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, the parameterless MessagePackInputFormatter constructor uses default serializer options, which resolve to MessagePackSerializerOptions.Standard with MessagePackSecurity.TrustedData. The formatter is designed for...

CVE-2026-48511

Summary: CVE-2026-48511 affects MessagePack for C# where ExpandoObjectFormatter.Deserialize inserts map entries into ExpandoObject via IDictionary.Add. This insertion pattern, coupled with ExpandoObject’s internal array-like member storage, can trigger repeated linear scans and array copies, caus...

CVE-2026-48511 MessagePack-CSharp: ExpandoObject formatter can perform quadratic insertion work on untrusted maps

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, ExpandoObjectFormatter.Deserialize populates System.Dynamic.ExpandoObject by calling IDictionary.Add for each map entry. ExpandoObject internally maintains member names in array-like structures, so inserting many...

CVE-2026-48512

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's JSON conversion helpers contain multiple recursion paths that do not consistently enforce a depth limit. These paths are in the JSON conversion component rather than normal typed MessagePack...

CVE-2026-48513

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.DepthStepref reader and do not decrement reader.Depth around recursive deserialization and skip paths. This means...

CVE-2026-48513 MessagePack-CSharp: DynamicUnionResolver generated deserializers miss depth enforcement

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.DepthStepref reader and do not decrement reader.Depth around recursive deserialization and skip paths. This means...

CVE-2026-48515 MessagePack-CSharp: Multi-dimensional array formatters allocate from unchecked dimensions

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's multi-dimensional array formatters read dimension lengths directly from the payload and allocate T,, T,,, or T,,, before validating that the dimension product matches the encoded element count. T...

CVE-2026-48515

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's multi-dimensional array formatters read dimension lengths directly from the payload and allocate T,, T,,, or T,,, before validating that the dimension product matches the encoded element count. T...

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-CSharp: InterfaceLookupFormatter bypasses collision-resistant comparer settings

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-...