{
  "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-2026-4339",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-4339",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-06-26T14:44:58.655Z",
    "updatedAt": "2026-06-26T15:40:33.300Z",
    "importedAt": "2026-10-24T01:58:14.884Z",
    "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": "SSRF via unvalidated attachment URLs in Mattermost Agents plugin MCP server",
      "summary": "Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to validate attachment URLs against internal or private IP ranges in the Mattermost Agents plugin MCP server which allows an attacker with access to the MCP server in stdio mode to perform server-side request forgery (SSRF) and exfiltrate data from internal network services via supplying internal URLs as file attachments in post creation requests.. Mattermost Advisory ID: MMSA-2026-00635",
      "affected": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "10.11.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "10.11.18"
            },
            {
              "version": "11.6.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.6.3"
            },
            {
              "version": "11.5.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.5.6"
            },
            {
              "version": "11.7.0",
              "status": "unaffected"
            },
            {
              "version": "10.11.19",
              "status": "unaffected"
            },
            {
              "version": "11.6.4",
              "status": "unaffected"
            },
            {
              "version": "11.5.7",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  }
}