{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48516","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-21T16:18:10.619Z","datePublished":"2026-06-22T21:09:51.787Z","dateUpdated":"2026-06-25T15:54:33.529Z"},"containers":{"cna":{"title":"MessagePack-CSharp: InterfaceLookupFormatter bypasses collision-resistant comparer settings","problemTypes":[{"descriptions":[{"cweId":"CWE-407","lang":"en","description":"CWE-407: Inefficient Algorithmic Complexity","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"references":[{"name":"https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8","tags":["x_refsource_CONFIRM"],"url":"https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8"}],"affected":[{"vendor":"MessagePack-CSharp","product":"MessagePack-CSharp","versions":[{"version":">= 3.0, < 3.1.7","status":"affected"},{"version":"< 2.5.301","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-06-25T15:54:33.529Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-q2h6-ghwm-5qm8","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-23T12:28:14.996422Z","id":"CVE-2026-48516","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-23T12:28:23.531Z"}}]}}