{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-21386",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-21386",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-03-16T14:51:43.263Z",
    "updatedAt": "2026-03-16T18:39:14.064Z",
    "importedAt": "2026-10-24T01:57:55.771Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "Private channel enumeration via /mute slash command",
      "summary": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexistent versus private channels. Mattermost Advisory ID: MMSA-2026-00588",
      "affected": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "11.3.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.3.0"
            },
            {
              "version": "11.2.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.2.2"
            },
            {
              "version": "10.11.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "10.11.10"
            },
            {
              "version": "11.4.0",
              "status": "unaffected"
            },
            {
              "version": "11.3.1",
              "status": "unaffected"
            },
            {
              "version": "11.2.3",
              "status": "unaffected"
            },
            {
              "version": "10.11.11",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  }
}