{"id":"CVE-2026-33393","aliases":["BIT-discourse-2026-33393","EUVD-2026-13338","GHSA-95r5-p6qr-hgw6"],"status":"published","title":"Discourse fixes loose hostname matching in spam host allowlist","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00267,"percentile":0.18981,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-284"],"published":"2026-03-19T22:04:26Z","modified":"2026-10-28T02:30:25Z","fixes":[{"ecosystem":"Bitnami","package":"discourse","fixed_in":["2026.1.2","2026.2.1","2026.3.0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"discourse","ranges":[{"type":"SEMVER","events":[{"introduced":"2026.1.0"},{"fixed":"2026.1.2"},{"introduced":"2026.2.0"},{"fixed":"2026.2.1"},{"introduced":"2026.3.0"},{"fixed":"2026.3.0"}]}]}],"products":[{"vendor":"discourse","product":"discourse"}],"references":[{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory"]},{"url":"https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33393","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33393.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-33393","title":"Discourse fixes loose hostname matching in spam host allowlist","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","status":"published","published":"2026-03-19T22:04:26.484Z","modified":"2026-03-20T20:15:16.294Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:20:08.009733Z"}],"euvd":[{"id":"EUVD-2026-13338","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","status":"published","published":"2026-03-19T22:04:26Z","modified":"2026-03-20T20:15:16Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T19:25:32.04432Z"}],"nvd":[{"id":"CVE-2026-33393","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","status":"published","published":"2026-03-19T22:16:42.497Z","modified":"2026-06-17T10:37:24.87Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:12:10.126802Z"}],"osv":[{"id":"CVE-2026-33393","title":"Discourse fixes loose hostname matching in spam host allowlist","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","status":"published","published":"2026-03-19T22:04:26.484Z","modified":"2026-10-28T02:30:25.312364126Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"BIT-discourse-2026-33393","title":"Discourse fixes loose hostname matching in spam host allowlist","description":"Discourse is an open-source discussion platform. Prior to versions 2026.3.0, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.","status":"published","published":"2026-03-27T07:10:50.748Z","modified":"2026-09-08T08:46:30.849261454Z","updated_at":"2026-11-02T15:28:29.152062Z"}]}}