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CVE-2026-33411

Status: AnalyzedMedium (5.4)—

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a potential stored XSS in topic titles for the solved posts stream. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Discourse — Discourse

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-33411",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-33411",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-03-24T18:02:39.477033Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.4,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.5,
        "exploitabilityScore": 2.8
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 5.4,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.7,
        "exploitabilityScore": 2.3
      }
    ]
  },
  "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"
            },
            {
              "status": "affected",
              "version": "= 2026.3.0-latest"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-03-20T23:16:47.660",
  "references": [
    {
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-j3mm-ghh2-83x2",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a potential stored XSS in topic titles for the solved posts stream. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks."
    },
    {
      "lang": "es",
      "value": "Discourse es una plataforma de discusión de código abierto. Las versiones anteriores a 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 tienen un XSS almacenado potencial en los títulos de los temas para el flujo de publicaciones resueltas. Las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 contienen un parche. Como solución alternativa, asegúrese de que la Política de Seguridad de Contenido esté habilitada y no haya sido modificada de una manera que la haría más vulnerable a ataques XSS."
    }
  ],
  "lastModified": "2026-06-17T10:37:26.910",
  "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"
}