{"id":"CVE-2026-46349","aliases":["BIT-mastodon-2026-46349","EUVD-2026-39054","GHSA-chgx-jx3p-rf73"],"status":"published","title":"Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring","description":"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.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00195,"percentile":0.09316,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-347"],"published":"2026-06-24T19:40:35Z","modified":"2026-10-28T02:30:41Z","fixes":[{"ecosystem":"Bitnami","package":"mastodon","fixed_in":["4.5.10"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"mastodon","ranges":[{"type":"SEMVER","events":[{"introduced":"4.5.0"},{"fixed":"4.5.10"}]}]}],"products":[{"vendor":"mastodon","product":"mastodon"}],"references":[{"url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73","tags":["x_refsource_CONFIRM","web","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46349","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46349.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-46349","title":"Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring","description":"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.","status":"published","published":"2026-06-24T19:40:35.022Z","modified":"2026-06-25T13:16:49.851Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T13:47:06.353366Z"}],"euvd":[{"id":"EUVD-2026-39054","description":"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.","status":"published","published":"2026-06-24T19:40:35Z","modified":"2026-06-25T13:16:49Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:20:29.213001Z"}],"nvd":[{"id":"CVE-2026-46349","description":"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.","status":"published","published":"2026-06-24T20:16:32.233Z","modified":"2026-06-25T16:32:07.257Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:12:25.67873Z"}],"osv":[{"id":"CVE-2026-46349","title":"Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring","description":"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.","status":"published","published":"2026-06-24T19:40:35.022Z","modified":"2026-10-28T02:30:41.199272749Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:45:05.870292Z"},{"id":"BIT-mastodon-2026-46349","title":"Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring","description":"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.","status":"published","published":"2026-07-06T05:55:15.922Z","modified":"2026-07-08T08:11:21.463068028Z","updated_at":"2026-11-02T15:28:32.645004Z"}]}}