EUVD-2026-38380

MessagePack-CSharp: InterfaceLookupFormatter bypasses collision-resistant comparer settings...

EUVD-2026-38381

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

GHSA-CJ9G-3MJ2-G8VV MessagePack-CSharp: JSON conversion APIs can recurse without consistent depth enforcement

Summary 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 deserialization. Three related issues are covered by this advisory: 1...

EUVD-2026-38384

MessagePack-CSharp: JSON conversion APIs can recurse without consistent depth enforcement...

EUVD-2026-38385

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

EUVD-2026-38389

MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows...

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-2026-48515

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-2026-48512

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-2026-48509

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-2026-48502

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-2026-48109 MessagePack-CSharp: LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input

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-2026-48109

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-2026-48109

CVE-2026-48109 affects MessagePack-CSharp in the optional LZ4 decompression path (Lz4Block, Lz4BlockArray). The vulnerability stems from a deprecated fast-decompression algorithm that does not enforce a source-length bound, enabling a remote attacker to craft payloads with manipulated LZ4 token/l...

CVE-2026-48109 MessagePack-CSharp: LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input

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-2026-48502 MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows

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-2026-48506

The CVE-2026-48506 entry concerns MessagePack-CSharp: MessagePackReader.TrySkip() can recurse without incrementing depth checks, bypassing MaximumObjectGraphDepth and risking unbounded recursion leading to StackOverflow. Affected: MessagePack-CSharp (reader Skip usage in nested arrays/maps). Root...

CVE-2026-48506 MessagePack-CSharp: MessagePackReader.Skip can recurse without enforcing maximum object graph depth

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, MessagePackReader.TrySkip recursively descends into nested arrays and maps without incrementing the reader depth or calling the configured depth checks. This bypasses MessagePackSecurity.MaximumObjectGraphDepth, the...