{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "\u003ca href=\"https://enklypesalt.com/\"\u003eH\u0026#229;kon M\u0026#229;l\u0026#248;y\u003c/a\u003e"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Moderate"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      },
      {
        "category": "general",
        "text": "Required. The vulnerability documented by this CVE requires customer action to resolve.",
        "title": "Customer Action"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-55145 Outlook Copilot Tampering Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55145"
      },
      {
        "category": "self",
        "summary": "CVE-2026-55145 Outlook Copilot Tampering Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-55145.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Exploitability Index",
        "url": "https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Outlook Copilot Tampering Vulnerability",
    "tracking": {
      "current_release_date": "2026-07-14T07:00:00.000Z",
      "generator": {
        "date": "2026-07-14T20:05:38.242Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-55145",
      "initial_release_date": "2026-07-14T07:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-07-14T07:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-55145",
      "cwe": {
        "id": "CWE-77",
        "name": "Improper Neutralization of Special Elements used in a Command (\u0027Command Injection\u0027)"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "Customers can help protect themselves by enabling Outlook\u0027s external sender tagging feature to identify untrusted content. This enables Microsoft\u0027s provided mitigations to isolate and safely process the untrusted content before it is provided to Microsoft 365 Copilot. Administrators can enable external sender tagging through Exchange Online PowerShell. Refer to the Microsoft Learn documentation for setup instructions and requirements.\nInstall the Exchange Online PowerShell Module, Connect to Exchange Online PowerShell, Set-ExternalInOutlook",
          "title": "How do I protect myself from this vulnerability?"
        }
      ],
      "product_status": {
        "fixed": [
          "21063"
        ],
        "known_affected": [
          "1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-55145 Outlook Copilot Tampering Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55145"
        },
        {
          "category": "self",
          "summary": "CVE-2026-55145 Outlook Copilot Tampering Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-55145.json"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "environmentalScore": 0.0,
            "exploitCodeMaturity": "PROOF_OF_CONCEPT",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 5.7,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N/E:P/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Tampering"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No"
        }
      ],
      "title": "Outlook Copilot Tampering Vulnerability"
    }
  ]
}