GHSA-F8H2-VMM9-QHJ6 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...

Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : .NET vulnerabilities (USN-8420-1)

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8420-1 advisory. It was discovered that .NET did not properly handle link resolution before file access. A local attacker could use this...

MessagePack's LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input

Impact 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 does not take a source-length bound. A remote attacker can send a crafted...

GHSA-HV8M-JJ95-WG3X MessagePack's LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input

Impact 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 does not take a source-length bound. A remote attacker can send a crafted...

Out-of-bounds Read

Overview MessagePack is a MessagePackMsgPack Serializer for C.NET, .NET Core, Unity, Xamarin. Affected versions of this package are vulnerable to Out-of-bounds Read in the LZ4 decompression path for Lz4Block and Lz4BlockArray modes. An attacker can cause process termination or potentially access...

USN-8420-1: .NET vulnerabilities

It was discovered that .NET did not properly handle link resolution before file access. A local attacker could use this issue to perform unauthorized file tampering and write arbitrary files outside of the intended extraction directory. CVE-2026-45491 It was discovered that .NET did not properly...

USN-8420-1 dotnet8, dotnet9, dotnet10 vulnerabilities

It was discovered that .NET did not properly handle link resolution before file access. A local attacker could use this issue to perform unauthorized file tampering and write arbitrary files outside of the intended extraction directory. CVE-2026-45491 It was discovered that .NET did not properly...

PT-2026-48814

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 An issue exists in the optional LZ4 decompression path used by compression modes Lz4Block and Lz4BlockArray. The decoder uses a deprecated...

CVE-2026-44375

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the...

Inefficient CPU Computation

Overview Nerdbank.MessagePack is an A modern, fast and NativeAOT-compatible MessagePack serialization library Affected versions of this package are vulnerable to Inefficient CPU Computation in the WithExpandoObjectConverter. An attacker can cause excessive CPU consumption by deserializing special...

GHSA-92VJ-HP7M-GWCJ Nerdbank.MessagePack has Inefficient CPU Computation

Impact Applications that call OptionalConverters.WithExpandoObjectConverter and deserialize untrusted data are open to a vulnerability by which an attacker can exploit a On² algorithm to burn an inordinate amount of CPU effort by adding a great many properties to an ExpandoObject, whose Add metho...

Nerdbank.MessagePack has Inefficient CPU Computation

Impact Applications that call OptionalConverters.WithExpandoObjectConverter and deserialize untrusted data are open to a vulnerability by which an attacker can exploit a On² algorithm to burn an inordinate amount of CPU effort by adding a great many properties to an ExpandoObject, whose Add metho...

Nerdbank.MessagePack has a memory amplification DoS in collection deserialization

Nerdbank.MessagePack deserializers for many collection-shaped types trusted the element count declared in MessagePack array and map headers when allocating destination storage. A crafted payload could therefore force large arrays, pooled buffers, dictionaries, or collection instances to be...

GHSA-QJVR-435C-5FJH Nerdbank.MessagePack has a memory amplification DoS in collection deserialization

Nerdbank.MessagePack deserializers for many collection-shaped types trusted the element count declared in MessagePack array and map headers when allocating destination storage. A crafted payload could therefore force large arrays, pooled buffers, dictionaries, or collection instances to be...

EUVD-2026-31426

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to properly validate msgpack-encoded WebSocket frames before memory allocation which allows an unauthenticated remote attacker to crash the server process and cause a full service outage for all users v...

CVE-2026-44375

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the...

CVE-2026-44375 Nerdbank.MessagePack: Attacker-controlled stackalloc in DateTime decoding causes process-terminating StackOverflowException

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the...

CVE-2026-44375 Nerdbank.MessagePack: Attacker-controlled stackalloc in DateTime decoding causes process-terminating StackOverflowException

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the...

CVE-2026-44375

The CVE-2026-44375 entry affects Nerdbank.MessagePack. The vulnerability arises in DateTime decoding where the reader can be fed a malicious MessagePack payload declaring an oversized timestamp extension length, enabling an attacker-controlled amount of stack memory to be allocated via stackalloc...

CVE-2026-44375 Nerdbank.MessagePack: Attacker-controlled stackalloc in DateTime decoding causes process-terminating StackOverflowException

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the...