CVE-2020-5234: Messagepack

Medium severity, CVSS 6.5. EPSS: 1.6% chance of exploitation in the next 30 days.

MessagePack for C# and Unity before version 1.9.11 and 2.1.90 has a vulnerability where untrusted data can lead to DoS attack due to hash collisions and stack overflow. Review the linked GitHub Security Advisory for more information and remediation steps.

Affected products

• Messagepack Messagepack: before 1.9.3 (fixed in 1.9.3); from 2.0.323, before 2.1.80 (fixed in 2.1.80); version 2.0.94 only; version 2.0.110 only; version 2.0.119 only; version 2.0.123 only; …

Published 2020-01-31. Last modified 2026-06-17.