{"id":"CVE-2026-47746","state":"PUBLISHED","title":"Misskey: JSON-LD signature validation + compaction is vulnerable to timing attacks","description":"Misskey is an open source, federated social media platform. Versions 12.37.0 and later, but prior to 2026.5.4, are vulnerable to timing attacks during JSON-LD signature validation and the compaction process. Because the JSON-LD parsing context is not shared between signature verification and subsequent processing, the application may trust information that should not be trusted, resulting in a time-of-check to time-of-use (TOCTOU) flaw. This allows an attacker to have fraudulent activities accepted as valid, leading to a loss of integrity. This issue has been fixed in version 2026.5.4.","publishedAt":"2026-08-03T21:56:40.198Z","updatedAt":"2026-08-04T14:11:19.206Z","severity":{"score":8.9,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["misskey-dev misskey"],"affected":[{"vendor":"misskey-dev","product":"misskey","versions":[{"version":">= 12.37.0, < 2026.5.4","status":"affected"}]}],"references":["https://github.com/misskey-dev/misskey/security/advisories/GHSA-38jx-423m-g387","https://github.com/misskey-dev/misskey/releases/tag/2026.5.4"],"weaknesses":["CWE-367"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/47xxx/CVE-2026-47746.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47746","state":"PUBLISHED","datePublished":"2026-08-03T21:56:40.198Z","dateUpdated":"2026-08-04T14:11:19.206Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-19T22:16:39.504Z"},"containers":{"cna":{"title":"Misskey: JSON-LD signature validation + compaction is vulnerable to timing attacks","descriptions":[{"lang":"en","value":"Misskey is an open source, federated social media platform. Versions 12.37.0 and later, but prior to 2026.5.4, are vulnerable to timing attacks during JSON-LD signature validation and the compaction process. Because the JSON-LD parsing context is not shared between signature verification and subsequent processing, the application may trust information that should not be trusted, resulting in a time-of-check to time-of-use (TOCTOU) flaw. This allows an attacker to have fraudulent activities accepted as valid, leading to a loss of integrity. This issue has been fixed in version 2026.5.4."}],"affected":[{"vendor":"misskey-dev","product":"misskey","versions":[{"version":">= 12.37.0, < 2026.5.4","status":"affected"}]}],"references":[{"url":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-38jx-423m-g387","name":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-38jx-423m-g387","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/misskey-dev/misskey/releases/tag/2026.5.4","name":"https://github.com/misskey-dev/misskey/releases/tag/2026.5.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","baseScore":8.9,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-367","lang":"en","description":"CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-03T21:56:40.198Z"},"source":{"advisory":"GHSA-38jx-423m-g387","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-04T14:11:08.087443Z","id":"CVE-2026-47746","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-04T14:11:19.206Z"}}]}}}