{"id":"CVE-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":["BIT-mastodon-2026-41259","GHSA-5r37-qpwq-2jhh"],"modified":"2026-07-08T08:26:07.897097117Z","published":"2026-04-23T18:55:20.854Z","database_specific":{"cwe_ids":["CWE-841"],"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41259.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41259.json"},{"type":"ADVISORY","url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41259"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mastodon/mastodon","events":[{"introduced":"0"},{"fixed":"128393e2b4be5e7472fe4d59edd63d7b927831e5"},{"introduced":"69e14246b838443985a541e97327494b8d2fdffb"},{"fixed":"7cbce428fd9f7b34f3d879417f0722f131e9d01f"},{"introduced":"26c78392f88afccebb8a88b68bc9994a9ce12648"},{"fixed":"ff7266cf38935cea896db714d94c4ca3803d7744"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"4.3.22"},{"introduced":"4.4.0"},{"fixed":"4.4.16"},{"introduced":"4.5.0"},{"fixed":"4.5.9"}]}}],"versions":["v4.3.21","v4.4.15","v4.5.8","v4.3.20","v4.4.14","v4.5.7","v4.3.19","v4.5.6","v4.4.13","v4.3.18","v4.4.12","v4.5.5","v4.5.4","v4.4.11","v4.3.17","v4.5.3","v4.3.16","v4.4.10","v4.5.2","v4.4.9","v4.3.15","v4.5.1","v4.5.0","v4.4.8","v4.3.14","v4.4.7","v4.4.6","v4.4.5","v4.3.13","v4.3.12","v4.4.4","v4.3.11","v4.4.3","v4.3.10","v4.4.2","v4.4.1","v4.4.0","v4.3.9","v4.3.8","v4.3.7","v4.3.6","v4.3.5","v4.3.4","v4.3.3","v4.3.2","v4.3.1","v4.3.0","v4.3.0-rc.1","v4.3.0-beta.2","v4.3.0-beta.1","v4.2.0","v4.2.0-rc2","v4.2.0-rc1","v4.2.0-beta3","v4.2.0-beta2","v4.2.0-beta1","v4.0.2","v4.1.0","v4.1.0rc3","v4.1.0rc2","v4.1.0rc1","v4.0.1","v4.0.0","v4.0.0rc4","v3.5.3","v4.0.0rc3","v4.0.0rc2","v4.0.0rc1","v3.5.2","v3.5.1","v3.5.0","v3.5.0rc3","v3.5.0rc2","v3.5.0rc1","v3.3.0","v3.4.1","v3.4.0","v3.4.0rc2","v3.4.0rc1","v3.3.0rc3","v3.3.0rc2","v3.3.0rc1","v3.2.0","v3.2.0rc2","v3.2.0rc1","v3.1.4","v3.1.3","v3.1.2","v3.0.1","v3.1.1","v3.1.0","v3.1.0rc2","v3.1.0rc1","v3.0.0","v3.0.0rc3","v3.0.0rc2","v3.0.0rc1","v2.9.2","v2.9.1","v2.9.0","v2.9.0rc2","v2.9.0rc1","v2.8.2","v2.8.1","v2.8.0","v2.8.0rc3","v2.8.0rc2","v2.8.0rc1","v2.7.1","v2.7.0","v2.7.0rc3","v2.7.0rc2","v2.7.0rc1","v2.6.1","v2.6.0","v2.6.0rc4","v2.6.0rc3","v2.6.0rc2","v2.6.0rc1","v2.5.0","v2.5.0rc2","v2.5.0rc1","v2.4.3","v2.4.3rc3","v2.4.3rc2","v2.4.3rc1","v2.4.2","v2.4.2rc3","v2.4.2rc2","v2.4.2rc1","v2.4.1","v2.4.1rc4","v2.4.1rc3","v2.4.1rc2","v2.4.1rc1","v2.4.0","v2.4.0rc5","v2.4.0rc4","v2.4.0rc3","v2.4.0rc2","v2.4.0rc1","v2.3.2","v2.3.2rc5","v2.3.2rc4","v2.3.2rc3","v2.3.2rc2","v2.3.2rc1","v2.3.1","v2.3.1rc3","v2.3.1rc2","v2.3.1rc1","v2.3.0","v2.3.0rc3","v2.3.0rc2","v2.3.0rc1","v2.2.0","v2.2.0rc2","v2.2.0rc1","v2.1.3","v2.1.2","v2.1.1","v2.1.0","v2.1.0rc6","v2.1.0rc5","v2.1.0rc4","v2.1.0rc3","v2.1.0rc2","v2.1.0rc1","v2.0.0","v2.0.0rc4","v2.0.0rc3","v2.0.0rc2","v2.0.0rc1","v1.6.1","v1.6.0","v1.6.0rc5","v1.6.0rc4","v1.6.0rc3","v1.6.0rc2","v1.6.0rc1","v1.5.1","v1.5.0","v1.5.0rc3","v1.5.0rc2","v1.5.0rc1","v1.4.7","v1.4.6","v1.4.5","v1.4.4","v1.4.3","v1.4.2","v1.4.1","v1.4rc6","v1.4rc5","v1.4rc4","v1.4rc3","v1.4rc2","v1.4rc1","v1.3.2","v1.3.1","v1.3","v1.2.2","v1.2.1","v1.2","v1.1.2","v1.1.1","v1.1","v1.0","v0.9.9","v0.9","v0.8","v0.7","v0.6","v0.1.2","v0.1.1","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41259.json"}}],"schema_version":"1.7.5","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"}]}