MessagePack: Nested arrays can blow past buffer length limits

Impact MessagePack-CSharp is vulnerable to denial of service through excessive memory allocation when deserializing attacker-controlled data into System.Object. When PrimitiveObjectFormatter encounters an array, it allocates an object using the declared array length before enforcing the configure...

GHSA-QHRR-8Q5H-9Q3H MessagePack: Nested arrays can blow past buffer length limits

Impact MessagePack-CSharp is vulnerable to denial of service through excessive memory allocation when deserializing attacker-controlled data into System.Object. When PrimitiveObjectFormatter encounters an array, it allocates an object using the declared array length before enforcing the configure...

MessagePack-CSharp Resource Management Vulnerability

Versions of MessagePack-CSharp prior to 2.5.303 and 3.1.9 contain a resource management vulnerability. This vulnerability arises from the PrimitiveObjectFormatter class, which improperly controls memory allocation when deserializing MessagePack data into System.Object. It allocates object based o...

MessagePack-CSharp Denial of Service Vulnerability

Improperly controlled sequential memory allocation in .NET allows an unauthorized attacker to deny service over a network...

CVE-2026-92707

Impact MessagePack-CSharp is vulnerable to denial of service through excessive memory allocation when deserializing attacker-controlled data into "System.Object". When "PrimitiveObjectFormatter" encounters an array, it allocates an "object" using the declared array length before enforcing the...

PT-2026-113552

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.303 MessagePack for C versions prior to 3.1.9 Description Deserializing attacker-controlled MessagePack data as System.Object through the PrimitiveObjectFormatter function can lead to excessive memory...

MessagePack-CSharp: Typeless deserialization type restrictions do not recurse into arrays or generic arguments

Summary MessagePack-CSharp's typeless deserialization includes MessagePackSerializerOptions.ThrowIfDeserializingTypeIsDisallowedType as a safety check for dangerous types. The default implementation checks the outer type name, but it does not recursively inspect array element types or generic typ...

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...

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-2026-38389

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

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

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-2026-48109 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: 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...

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-2026-48509

CVE-2026-48509 affects MessagePack for C# (ASP.NET Core MVC context). The issue is that, prior to versions 2.5.301 and 3.1.7, the parameterless MessagePackInputFormatter() uses default serializer options that resolve to Standard with MessagePackSecurity.TrustedData, which can cross HTTP trust bou...

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...