{"id":"CVE-2026-33393","state":"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.","publishedAt":"2026-03-19T22:04:26.484Z","updatedAt":"2026-03-20T20:15:16.294Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["discourse discourse"],"affected":[{"vendor":"discourse","product":"discourse","versions":[{"version":">= 2026.1.0-latest, < 2026.1.2","status":"affected"},{"version":">= 2026.2.0-latest, < 2026.2.1","status":"affected"},{"version":"= 2026.3.0-latest","status":"affected"}]}],"references":["https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6","https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2","https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02","https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e"],"weaknesses":["CWE-284"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/33xxx/CVE-2026-33393.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33393","state":"PUBLISHED","datePublished":"2026-03-19T22:04:26.484Z","dateUpdated":"2026-03-20T20:15:16.294Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-19T17:02:34.169Z"},"containers":{"cna":{"title":"Discourse fixes loose hostname matching in spam host allowlist","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"discourse","product":"discourse","versions":[{"version":">= 2026.1.0-latest, < 2026.1.2","status":"affected"},{"version":">= 2026.2.0-latest, < 2026.2.1","status":"affected"},{"version":"= 2026.3.0-latest","status":"affected"}]}],"references":[{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6","name":"https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2","name":"https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02","name":"https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e","name":"https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-284","lang":"en","description":"CWE-284: Improper Access Control","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-03-19T22:04:26.484Z"},"source":{"advisory":"GHSA-95r5-p6qr-hgw6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-20T20:15:06.393968Z","id":"CVE-2026-33393","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-20T20:15:16.294Z"}}]}}}