MessagePack-CSharp: DynamicUnionResolver generated deserializers miss depth enforcement_CVE-2026-48513

6.3 / 10

MEDIUM

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Description

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, runtime-generated union deserializers emitted by DynamicUnionResolver do not call MessagePackSecurity.DepthStep(ref reader) and do not decrement reader.Depth around recursive deserialization and skip paths. This means union deserialization does not consistently participate in the maximum object graph depth enforcement that protects other recursive formatter paths. For unknown union keys, the emitted deserializer calls reader.Skip() on attacker-controlled data without an enclosing depth step. This vulnerability is fixed in 2.5.301 and 3.1.7.

Basic Information

ID CVE-2026-48513

Source GitHub_M

Published Jun 22, 2026 at 21:12

Affected Product

Vendor MessagePack-CSharp

Product MessagePack-CSharp

Version >= 3.1.7, < 3.1.7

Affected Versions MessagePack-CSharp MessagePack-CSharp >= 3.1.7, < 3.1.7
MessagePack-CSharp MessagePack-CSharp < 2.5.301

CWE Classification

CWE-674

References

github.com /MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwh

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    "published": "2026-06-22T21:12:43.104Z",
    "modified": "2026-06-22T21:12:43.104Z",
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