CVE-2026-33393

{"id": "CVE-2026-33393", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 2.8}]}, "published": "2026-03-19T22:16:42.497", "references": [{"url": "https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-284"}]}], "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."}, {"lang": "es", "value": "Discourse es una plataforma de discusi\u00f3n de c\u00f3digo abierto. Antes de las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2, la verificaci\u00f3n 'allowed_spam_host_domains' utilizaba 'String#end_with?' sin validaci\u00f3n de l\u00edmites de dominio, lo que permit\u00eda que dominios como 'attacker-example.com' eludieran la protecci\u00f3n contra el correo no deseado cuando 'example.com' estaba en lista blanca. Las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 requieren una coincidencia exacta o una coincidencia de subdominio adecuada (precedida por '.') para evitar la elusi\u00f3n basada en sufijos de 'newuser_spam_host_threshold'. No hay soluciones alternativas conocidas disponibles."}], "lastModified": "2026-03-24T20:41:57.427", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4BE96625-3609-410C-B41E-4A824C1A57C0", "versionEndExcluding": "2026.1.2", "versionStartIncluding": "2026.1.0"}, {"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FD31CF04-CF2F-4FB9-8880-9243BC7671A7", "versionEndExcluding": "2026.2.1", "versionStartIncluding": "2026.2.0"}, {"criteria": "cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*", "vulnerable": true, "matchCriteriaId": "E3FE9277-4F6B-4FD0-991F-F0FB8D226E1C"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}