FKIE_CVE-2026-107845

Vulnerability from fkie_nvd - Published: 2026-10-09 20:17 - Updated: 2026-10-09 20:17
Severity
9.3 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Summary
Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, an unauthenticated visitor can submit a comment whose email or website metadata is rendered without sufficient attribute and URL encoding by listComments() in comments-bundle/contao/dca/tl_comments.php. When a backend user opens the Comments module, attacker-controlled script can execute in the Contao backend origin under that user's session. Unpublished comments remain visible to moderators, so moderation does not prevent exposure. This issue is fixed in versions 5.3.50 and 5.7.12.
References
security-advisories@github.comhttps://github.com/contao/contao/commit/22505d5f79bc1a7f52e2cba5fddf6007e1f0408a
security-advisories@github.comhttps://github.com/contao/contao/releases/tag/5.3.50
security-advisories@github.comhttps://github.com/contao/contao/releases/tag/5.7.12
security-advisories@github.comhttps://github.com/contao/contao/security/advisories/GHSA-628f-v4f6-p37r
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "contao",
          "vendor": "contao",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 5.3.50"
            },
            {
              "status": "affected",
              "version": "\u003e= 5.4.0-RC1, \u003c 5.7.12"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, an unauthenticated visitor can submit a comment whose email or website metadata is rendered without sufficient attribute and URL encoding by listComments() in comments-bundle/contao/dca/tl_comments.php. When a backend user opens the Comments module, attacker-controlled script can execute in the Contao backend origin under that user\u0027s session. Unpublished comments remain visible to moderators, so moderation does not prevent exposure. This issue is fixed in versions 5.3.50 and 5.7.12."
    }
  ],
  "id": "CVE-2026-107845",
  "lastModified": "2026-10-09T20:17:10.457",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.8,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-107845",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-09T19:51:37.559746Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-09T20:17:10.457",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/contao/contao/commit/22505d5f79bc1a7f52e2cba5fddf6007e1f0408a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/contao/contao/releases/tag/5.3.50"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/contao/contao/releases/tag/5.7.12"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/contao/contao/security/advisories/GHSA-628f-v4f6-p37r"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-116"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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Nomenclature

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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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