CVE-2026-93851

{
  "id": "CVE-2026-93851",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-28T22:17:17.310",
  "lastModified": "2026-10-30T04:18:30.140",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10 fail to validate the target post ID in the Agents plugin's mention reminder component, which allows an authenticated user who can post in a channel visible to a system administrator to cause the administrator's browser to send an unintended API request, resulting in replacement of an installed plugin and code execution on the server, via a crafted post containing a forged mention reminder that the administrator clicks. Mattermost Advisory ID: MMSA-2026-00742"
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "11.9.0",
              "lessThanOrEqual": "11.9.1",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "11.8.0",
              "lessThanOrEqual": "11.8.5",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "11.7.0",
              "lessThanOrEqual": "11.7.10",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "11.10.0",
              "status": "unaffected"
            },
            {
              "version": "11.9.2",
              "status": "unaffected"
            },
            {
              "version": "11.8.6",
              "status": "unaffected"
            },
            {
              "version": "11.7.11",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "baseScore": 8.0,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "REQUIRED",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.3,
        "impactScore": 6.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-29T00:00:00+00:00",
          "id": "CVE-2026-93851",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://mattermost.com/security-updates",
      "source": "[email protected]"
    }
  ]
}