{"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"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-48516", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-23T12:28:14.996422Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-23T12:28:19.914Z"}}], "cna": {"title": "MessagePack-CSharp: InterfaceLookupFormatter bypasses collision-resistant comparer settings", "source": {"advisory": "GHSA-q2h6-ghwm-5qm8", "discovery": "UNKNOWN"}, "metrics": [{"cvssV4_0": {"version": "4.0", "baseScore": 6.3, "attackVector": "NETWORK", "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", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE"}}], "affected": [{"vendor": "MessagePack-CSharp", "product": "MessagePack-CSharp", "versions": [{"status": "affected", "version": ">= 3.0, < 3.1.7"}, {"status": "affected", "version": "< 2.5.301"}]}], "references": [{"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8", "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8", "tags": ["x_refsource_CONFIRM"]}], "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-407", "description": "CWE-407: Inefficient Algorithmic Complexity"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-06-25T15:54:33.529Z"}}}, "cveMetadata": {"cveId": "CVE-2026-48516", "state": "PUBLISHED", "dateUpdated": "2026-06-25T15:54:33.529Z", "dateReserved": "2026-05-21T16:18:10.619Z", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "datePublished": "2026-06-22T21:09:51.787Z", "assignerShortName": "GitHub_M"}, "dataVersion": "5.2"}

{}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.1.7,3.1.7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.5.301)"}}], "enrichment": {"confidence": 90.0, "confidence_source": "matching", "scores": [{"score": 90.0, "source": "matching"}]}, "original": {"product": "MessagePack-CSharp", "source": "cna", "vendor": "MessagePack-CSharp"}, "product": "messagepack-csharp", "vendor": "messagepack"}], "created": "2026-06-23T00:30:06.683210+00:00", "updated": "2026-06-24T16:07:26.614732+00:00", "vendors": ["messagepack", "messagepack$PRODUCT$messagepack-csharp"]}