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-2026-51394

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-2026-51397

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-2026-51396

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-2026-51393

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-2026-51390

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-2026-51399

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-2026-51392

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...

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...

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...

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...

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...

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...

Microsoft Security Advisory CVE-2026-45591 – ASP.NET Core Denial of Service Vulnerability

Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core SignalR and Blazor Server. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A denial of service...