{"id":"BIT-mastodon-2026-48028","summary":"Mastodon: Removal of integrity-protected JSON entries from signed activities","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 threat actors to remove JSON entries from valid signed activities from a third-party actor. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.","aliases":["CVE-2026-48028","GHSA-53m7-2wrh-q839"],"modified":"2026-07-08T08:11:10.561053549Z","published":"2026-07-06T05:55:20.384Z","database_specific":{"cpes":["cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*"],"severity":"Medium"},"references":[{"type":"WEB","url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-53m7-2wrh-q839"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48028"}],"affected":[{"package":{"name":"mastodon","ecosystem":"Bitnami","purl":"pkg:bitnami/mastodon"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.3.23"},{"introduced":"4.4.0"},{"fixed":"4.4.17"},{"introduced":"4.5.0"},{"fixed":"4.5.10"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/mastodon/BIT-mastodon-2026-48028.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L"}]}],"schema_version":"1.7.5"}