{"id":"BIT-mastodon-2026-41259","summary":"Mastodon: Insufficient verification of email addresses","details":"Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail domain names, and performs basic validation on e-mail addresses, but fails to restrict characters that are interpreted differently by some mailing servers. This vulnerability is fixed in v4.5.9, v4.4.16, and v4.3.22.","aliases":["CVE-2026-41259","GHSA-5r37-qpwq-2jhh"],"modified":"2026-09-08T08:48:13.008961466Z","published":"2026-04-27T09:00:33.489Z","database_specific":{"cpes":["cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*"],"severity":"High"},"references":[{"type":"ADVISORY","url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41259"}],"affected":[{"package":{"name":"mastodon","ecosystem":"Bitnami","purl":"pkg:bitnami/mastodon"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.3.22"},{"introduced":"4.4.0"},{"fixed":"4.4.16"},{"introduced":"4.5.0"},{"fixed":"4.5.9"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/mastodon/BIT-mastodon-2026-41259.json"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}],"schema_version":"1.9.0"}