CVE-2026-48517

CVE-2026-48517 affects MessagePack-CSharp (MessagePack for C#). The vulnerability arises because typeless deserialization’s safety check (ThrowIfDeserializingTypeIsDisallowed) only validates the outer type name and does not recursively inspect inner types such as array element types or generic ty...

CVE-2026-48517 MessagePack-CSharp: Typeless deserialization type restrictions do not recurse into arrays or generic arguments

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-2026-48517 MessagePack-CSharp: Typeless deserialization type restrictions do not recurse into arrays or generic arguments

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-2026-48517 MessagePack-CSharp: Typeless deserialization type restrictions do not recurse into arrays or generic arguments

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...

dotnet: ASP.NET Core: Denial of Service via uncontrolled resource consumption

A flaw was found in ASP.NET Core SignalR and Blazor Server. A remote attacker could send a specially crafted MessagePack payload containing deeply nested arrays that trigger excessive recursion and cause a stack overflow. This issue may result in application termination and a denial of service...

dotnet: ASP.NET Core: Denial of Service via uncontrolled resource consumption

A flaw was found in ASP.NET Core SignalR and Blazor Server. A remote attacker could send a specially crafted MessagePack payload containing deeply nested arrays that trigger excessive recursion and cause a stack overflow. This issue may result in application termination and a denial of service...

dotnet: ASP.NET Core: Denial of Service via uncontrolled resource consumption

A flaw was found in ASP.NET Core SignalR and Blazor Server. A remote attacker could send a specially crafted MessagePack payload containing deeply nested arrays that trigger excessive recursion and cause a stack overflow. This issue may result in application termination and a denial of service...

PT-2026-51397

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 Runtime-generated union deserializers emitted by DynamicUnionResolver fail to call MessagePackSecurity.DepthStepref reader and do not decrement...

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-2026-51393

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 parameterless MessagePackInputFormatter constructor uses default serializer options that resolve to MessagePackSerializerOptions.Standard wit...

PT-2026-51400

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 InterfaceLookupFormatter constructs an internal Dictionary using the default equality comparer instead of the security-aware comparer provide...

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-2026-51399

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...

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-2026-51390

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 MessagePack for C is a MessagePack serializer for C. The ReadDateTime function in MessagePackReader can allocate stack memory based on an...

PT-2026-51392

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 MessagePackReader.TrySkip function recursively descends into nested arrays and maps without incrementing the reader depth or triggering...

GHSA-6V7P-G79W-8964 MessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error

Impact If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack. Patches v1.2.1 Workarounds Users should create a new Unpacker instead of...

MessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error

Impact If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack. Patches v1.2.1 Workarounds Users should create a new Unpacker instead of...

PT-2026-54004

Name of the Vulnerable Software and Affected Versions MessagePack versions prior to 1.2.1 Description An out-of-bounds read occurs when an Unpacker is reused after an error has been caught, which can lead to a denial of service DoS attack. If the Unpacker is used repeatedly following such an erro...