{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "Kugelblitz with Microsoft"
        ]
      },
      {
        "names": [
          "Kugelblitz with Microsoft"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Important"
    },
    "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-2026-66798 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66798"
      },
      {
        "category": "self",
        "summary": "CVE-2026-66798 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-66798.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": "Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability",
    "tracking": {
      "current_release_date": "2026-08-28T07:00:00.000Z",
      "generator": {
        "date": "2026-09-09T19:34:20.831Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-66798",
      "initial_release_date": "2026-08-28T07:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-08-28T07:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for iOS <152.0.4191.52",
                  "product_id": "4"
                }
              },
              {
                "category": "product_version",
                "name": "152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for iOS 152.0.4191.52",
                  "product_id": "11966"
                }
              }
            ],
            "category": "product_name",
            "name": "Microsoft Edge for iOS"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for MAC <152.0.4191.52",
                  "product_id": "3"
                }
              },
              {
                "category": "product_version",
                "name": "152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for MAC 152.0.4191.52",
                  "product_id": "12480"
                }
              }
            ],
            "category": "product_name",
            "name": "Microsoft Edge for MAC"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Linux <152.0.4191.52",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Linux 152.0.4191.52",
                  "product_id": "21776"
                }
              }
            ],
            "category": "product_name",
            "name": "Microsoft Edge for Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Android <152.0.4191.52",
                  "product_id": "5"
                }
              },
              {
                "category": "product_version",
                "name": "152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Android 152.0.4191.52",
                  "product_id": "11815"
                }
              }
            ],
            "category": "product_name",
            "name": "Microsoft Edge for Android"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Windows <152.0.4191.52",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "152.0.4191.52",
                "product": {
                  "name": "Microsoft Edge for Windows 152.0.4191.52",
                  "product_id": "21777"
                }
              }
            ],
            "category": "product_name",
            "name": "Microsoft Edge for Windows"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-66798",
      "cwe": {
        "id": "CWE-416",
        "name": "Use After Free"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "This attack requires a client to connect to a malicious server, and that could allow the attacker to gain code execution on the client.",
          "title": "According to the CVSS metric, the attack vector is network (AV:N) and the user interaction is required (UI:R). What is the target context of the remote code execution?"
        },
        {
          "category": "faq",
          "text": "While we cannot rule out the impact to Confidentiality, Integrity, and Availability, the ability to exploit this vulnerability by itself is limited. An attacker would need to combine this with other vulnerabilities to perform an attack.",
          "title": "According to the CVSS metrics, successful exploitation of this vulnerability could lead to no loss of confidentiality (C:N) and  integrity (I:N), but could lead to some loss of availability (A:L). What does that mean for this vulnerability?"
        },
        {
          "category": "faq",
          "text": "The user must visit the attacker‑controlled webpage, and perform the two tap gestures that cause autofill to activate.",
          "title": "According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?"
        },
        {
          "category": "faq",
          "text": "152.0.4191.53: 152.0.4191.53, 08/28/2026: 08/28/2026, 152.0.7977.64/.65: 152.0.7977.64/.65",
          "title": "What is the version information for this release?"
        }
      ],
      "product_status": {
        "fixed": [
          "11655",
          "11815",
          "11966",
          "12480",
          "21776",
          "21777"
        ],
        "known_affected": [
          "1",
          "2",
          "3",
          "4",
          "5",
          "6"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-66798 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66798"
        },
        {
          "category": "self",
          "summary": "CVE-2026-66798 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-66798.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-08-28T07:00:00.000Z",
          "details": "152.0.4191.52:Security Update:https://learn.microsoft.com/en-us/DeployEdge/microsoft-edge-relnotes-security",
          "product_ids": [
            "4",
            "3",
            "2",
            "5",
            "1"
          ],
          "url": "https://learn.microsoft.com/en-us/DeployEdge/microsoft-edge-relnotes-security"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 3.8,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3",
            "4",
            "5",
            "6"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Remote Code Execution"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Unlikely"
        }
      ],
      "title": "Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability"
    }
  ]
}