MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large uncompressed length and force a large allocation before LZ4 decoding begins. This vulnerability is fixed in 2.5.301 and 3.1.7.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp
    decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and
    allocates output buffers based on those lengths before validating that the compressed data is valid or
    that the declared expansion is reasonable. A small payload can claim a very large uncompressed length and
    force a large allocation before LZ4 decoding begins. This vulnerability is fixed in 2.5.301 and 3.1.7.
    (CVE-2026-48510)

ID	Name	Product	Family	Type	Severity
461028	Echo: MessagePack: security update to 2.5.172+echo.1	Tenable Cloud Security	Echo Local Security Checks	Local	medium
461028	Echo: MessagePack: security update to 2.5.172+echo.1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
443986	SCA: security update for MessagePack (GHSA-v72x-2h86-7f8m)	Tenable Cloud Security	SCA Checks	Local	medium
443986	SCA: security update for MessagePack (GHSA-v72x-2h86-7f8m)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

Analytics

CVE-2026-48510

medium

Tenable Plugins

medium

medium

medium

medium