{"id":"CVE-2026-46349","summary":"Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring","details":"Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.","aliases":["BIT-mastodon-2026-46349","GHSA-chgx-jx3p-rf73"],"modified":"2026-07-15T01:49:07.102473282Z","published":"2026-06-24T19:40:35.022Z","database_specific":{"cwe_ids":["CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46349.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46349.json"},{"type":"ADVISORY","url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46349"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mastodon/mastodon","events":[{"introduced":"5a8ab0a3e62a8825e28bb74c1760ba6488d20c97"},{"fixed":"f80b1ba92e63c3da771b405b9100f5c9abda909f"}],"database_specific":{"extracted_events":[{"introduced":"4.5.0-beta.1"},{"fixed":"4.5.10"}],"source":"AFFECTED_FIELD"}}],"versions":["v4.5.9","v4.5.8","v4.5.7","v4.5.6","v4.5.5","v4.5.4","v4.5.3","v4.5.2","v4.5.1","v4.5.0","v4.5.0-rc.3","v4.5.0-rc.2","v4.5.0-rc.1","v4.5.0-beta.2","v4.5.0-beta.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46349.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}