{
  "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-2026-10556",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-10556",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-09-14T10:46:01.186Z",
    "updatedAt": "2026-09-14T11:19:44.241Z",
    "importedAt": "2026-10-24T01:57:50.502Z",
    "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": "Unauthenticated webhook request with null notification entry could crash the Microsoft Calendar plugin.",
      "summary": "Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate null entries in Microsoft Graph webhook notification payloads, which allows an unauthenticated attacker to crash the Microsoft Calendar plugin process and deny calendar integration service to all users on the instance via a crafted {{POST}} request to the public webhook endpoint.. Mattermost Advisory ID: MMSA-2026-00693",
      "affected": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "11.9.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.9.0"
            },
            {
              "version": "11.8.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.8.4"
            },
            {
              "version": "11.7.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "11.7.7"
            },
            {
              "version": "10.11.0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "10.11.22"
            },
            {
              "version": "11.10.0",
              "status": "unaffected"
            },
            {
              "version": "11.9.1",
              "status": "unaffected"
            },
            {
              "version": "11.8.5",
              "status": "unaffected"
            },
            {
              "version": "11.7.8",
              "status": "unaffected"
            },
            {
              "version": "10.11.23",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  }
}