cvedb.io
CVE-2026-48516
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-06-22T22:16:48.490 · Last modified 2026-06-25T17:16:39.540

Summary

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter<TKey,TElement> constructs an internal Dictionary<TKey, IGrouping<TKey,TElement>> with the default equality comparer instead of the security-aware comparer supplied by options.Security.GetEqualityComparer<TKey>(). This formatter omission allows hash-collision CPU denial of service against ILookup<TKey,TElement> even when the application has opted into the untrusted-data security posture This vulnerability is fixed in 2.5.301 and 3.1.7.

Affected products

messagepack — messagepack

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.