What is CVE-2026-48517?

CVE-2026-48517 is a high-severity vulnerability in Messagepack, classified under Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection). CVSS score: 7.5/10. Published 2026-06-22.

How severe is CVE-2026-48517?

High severity. CVSS v3 base score is 7.5 out of 10.

Deserialization in Messagepack

CVE-2026-48517

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.ThrowIfDeserializingTypeIsDisallowed(Type) as a safety check for dangero…

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Messagepack
Messagepack-csharp — versions >= 3.1.7, < 3.1.7, < 2.5.301

Weakness classification (CWE)

CWE-470 — Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection)
CWE-502 — Deserialization of Untrusted Data

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-48517?: CVE-2026-48517 is a high-severity vulnerability in Messagepack, classified under Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection). CVSS score: 7.5/10. Published 2026-06-22.
How severe is CVE-2026-48517?: High severity. CVSS v3 base score is 7.5 out of 10.