CVE-2026-33393

{
  "id": "CVE-2026-33393",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-33393",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-03-20T20:15:06.393968Z"
        }
      }
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    "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
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "discourse",
          "product": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": ">= 2026.1.0-latest, < 2026.1.2"
            },
            {
              "status": "affected",
              "version": ">= 2026.2.0-latest, < 2026.2.1"
            },
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              "status": "affected",
              "version": "= 2026.3.0-latest"
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  "published": "2026-03-19T22:16:42.497",
  "references": [
    {
      "url": "https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2",
      "tags": [
        "Patch"
      ],
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    },
    {
      "url": "https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02",
      "tags": [
        "Patch"
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    {
      "url": "https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e",
      "tags": [
        "Patch"
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      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6",
      "tags": [
        "Vendor Advisory"
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      "source": "security-advisories@github.com"
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  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "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 discusión de código abierto. Antes de las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2, la verificación 'allowed_spam_host_domains' utilizaba 'String#end_with?' sin validación de límites de dominio, lo que permitía que dominios como 'attacker-example.com' eludieran la protección 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 elusión basada en sufijos de 'newuser_spam_host_threshold'. No hay soluciones alternativas conocidas disponibles."
    }
  ],
  "lastModified": "2026-06-17T10:37:24.870",
  "configurations": [
    {
      "nodes": [
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          "negate": false,
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              "versionEndExcluding": "2026.1.2",
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  "sourceIdentifier": "security-advisories@github.com"
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