{"id":"BIT-mastodon-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":["CVE-2026-46349","GHSA-chgx-jx3p-rf73"],"modified":"2026-07-08T08:11:21.463068028Z","published":"2026-07-06T05:55:15.922Z","database_specific":{"severity":"Medium","cpes":["cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*"]},"references":[{"type":"WEB","url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46349"}],"affected":[{"package":{"name":"mastodon","ecosystem":"Bitnami","purl":"pkg:bitnami/mastodon"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.5.0"},{"fixed":"4.5.10"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/mastodon/BIT-mastodon-2026-46349.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}],"schema_version":"1.7.5"}