{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Mattermost",
          "vendor": "Mattermost",
          "versions": [
            {
              "lessThanOrEqual": "10.11.10",
              "status": "affected",
              "version": "10.11.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.4.0"
            },
            {
              "status": "unaffected",
              "version": "10.11.11"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "hackit_bharat"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost versions 10.11.x \u003c= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.8,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "CWE-863: Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-16T20:19:51.287Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "MMSA-2025-00531",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mattermost.com/security-updates"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost to versions 11.4.0, 10.11.11 or higher."
        }
      ],
      "source": {
        "advisory": "MMSA-2025-00531",
        "defect": [
          "https://mattermost.atlassian.net/browse/MM-66091"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Team Admin Privilege Escalation to Demote Members to Guest"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-26230",
    "datePublished": "2026-03-16T20:19:51.287Z",
    "dateReserved": "2026-02-13T10:39:47.088Z",
    "dateUpdated": "2026-03-16T20:19:51.287Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-26230\",\"sourceIdentifier\":\"responsibledisclosure@mattermost.com\",\"published\":\"2026-03-16T21:16:33.480\",\"lastModified\":\"2026-03-16T21:16:33.480\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Mattermost versions 10.11.x \u003c= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N\",\"baseScore\":3.8,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"HIGH\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.2,\"impactScore\":2.5}]},\"weaknesses\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-863\"}]}],\"references\":[{\"url\":\"https://mattermost.com/security-updates\",\"source\":\"responsibledisclosure@mattermost.com\"}]}}"
  }
}