{"id":"CVE-2026-47746","aliases":["EUVD-2026-52488","GHSA-38jx-423m-g387"],"status":"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.","severity":{"version":"4.0","score":8.9,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00282,"percentile":0.20817,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-367"],"published":"2026-08-03T21:56:40Z","modified":"2026-10-28T02:30:28Z","products":[{"vendor":"misskey-dev","product":"misskey"}],"references":[{"url":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-38jx-423m-g387","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/misskey-dev/misskey/releases/tag/2026.5.4","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47746.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47746","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-47746","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.","status":"published","published":"2026-08-03T21:56:40.198Z","modified":"2026-08-04T14:11:19.206Z","cvss":[{"version":"4.0","score":8.9,"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","level":"high","assessor":"cna"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T13:36:29.327819Z"}],"euvd":[{"id":"EUVD-2026-52488","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.","status":"published","published":"2026-08-03T21:56:40Z","modified":"2026-08-04T14:11:19Z","cvss":[{"version":"4.0","score":8.9,"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","level":"high"}],"updated_at":"2026-11-02T18:02:23.332335Z"}],"nvd":[{"id":"CVE-2026-47746","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.","status":"published","published":"2026-08-03T22:16:49.447Z","modified":"2026-10-23T21:10:00.157Z","cvss":[{"version":"4.0","score":8.9,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T14:12:34.643497Z"}],"osv":[{"id":"CVE-2026-47746","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.","status":"published","published":"2026-08-03T21:56:40.198Z","modified":"2026-10-28T02:30:28.94125318Z","cvss":[{"version":"4.0","score":8.9,"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","level":"high"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T15:45:06.231145Z"}]}}