{"id":"CVE-2026-50128","state":"PUBLISHED","title":"Mastodon: Spoofing of attribution domains","description":"Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18, Mastodon has a feature to let websites credit authors of their articles. To prevent false attribution claims, Mastodon uses the attributionDomains JSON-LD term, however, an error in how it is defined makes Linked Data Signatures on the toot:attributionDomains property ineffective. An attacker can arbitrarily modify the attributionDomains value of a legitimately signed Update activity and bypass Mastodon’s signature verification. This vulnerability is fixed in 4.5.11 and 4.4.18.","publishedAt":"2026-06-24T19:48:52.942Z","updatedAt":"2026-06-25T15:40:03.219Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["mastodon mastodon"],"affected":[{"vendor":"mastodon","product":"mastodon","versions":[{"version":">= 4.5.0-beta.1, < 4.5.11","status":"affected"},{"version":">= 4.3.0, < 4.4.18","status":"affected"}]}],"references":["https://github.com/mastodon/mastodon/security/advisories/GHSA-rwcw-vq68-g34p","https://github.com/gogs/gogs/security/advisories/GHSA-pwx3-qcgw-vh7h"],"weaknesses":["CWE-354"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/50xxx/CVE-2026-50128.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-50128","state":"PUBLISHED","datePublished":"2026-06-24T19:48:52.942Z","dateUpdated":"2026-06-25T15:40:03.219Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-03T18:49:32.275Z"},"containers":{"cna":{"title":"Mastodon: Spoofing of attribution domains","descriptions":[{"lang":"en","value":"Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18, Mastodon has a feature to let websites credit authors of their articles. To prevent false attribution claims, Mastodon uses the attributionDomains JSON-LD term, however, an error in how it is defined makes Linked Data Signatures on the toot:attributionDomains property ineffective. An attacker can arbitrarily modify the attributionDomains value of a legitimately signed Update activity and bypass Mastodon’s signature verification. This vulnerability is fixed in 4.5.11 and 4.4.18."}],"affected":[{"vendor":"mastodon","product":"mastodon","versions":[{"version":">= 4.5.0-beta.1, < 4.5.11","status":"affected"},{"version":">= 4.3.0, < 4.4.18","status":"affected"}]}],"references":[{"url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-rwcw-vq68-g34p","name":"https://github.com/mastodon/mastodon/security/advisories/GHSA-rwcw-vq68-g34p","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-354","lang":"en","description":"CWE-354: Improper Validation of Integrity Check Value","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-24T19:48:52.942Z"},"source":{"advisory":"GHSA-rwcw-vq68-g34p","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/gogs/gogs/security/advisories/GHSA-pwx3-qcgw-vh7h","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-25T15:39:17.708860Z","id":"CVE-2026-50128","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-25T15:40:03.219Z"}}]}}}