Mitigation bypass in the File Handling component

{
  "id": "df57818e5b72f7edbe00289f62c756dc413d92b4b72cf798e3da2fc0de931c19",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-109783",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Mitigation bypass in the File Handling component",
    "summary": "Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.",
    "evidence": "cve:CVE-2026-109783",
    "products": [
      {
        "name": {
          "value": "Firefox",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Thunderbird",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-109783",
      "aliases": [
        "CVE-2026-109783"
      ],
      "metrics": [],
      "affected": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "unaffected",
              "version": "153.5",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        },
        {
          "vendor": "Mozilla",
          "product": "Thunderbird",
          "versions": [
            {
              "status": "unaffected",
              "version": "153.5",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ],
      "modified": "2026-10-26T19:40:53.332Z",
      "provider": "cve",
      "references": [
        "https://bugzilla.mozilla.org/show_bug.cgi?id=2075533",
        "https://www.mozilla.org/security/advisories/mfsa2026-108/",
        "https://www.mozilla.org/security/advisories/mfsa2026-110/"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "cvssV3_1": {
                  "scope": "CHANGED",
                  "version": "3.1",
                  "baseScore": 8.3,
                  "attackVector": "NETWORK",
                  "baseSeverity": "HIGH",
                  "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H",
                  "integrityImpact": "HIGH",
                  "userInteraction": "REQUIRED",
                  "attackComplexity": "HIGH",
                  "availabilityImpact": "HIGH",
                  "privilegesRequired": "NONE",
                  "confidentialityImpact": "HIGH"
                }
              },
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-109783",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T19:24:56.139735Z"
                  }
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "lang": "en",
                    "type": "CWE",
                    "cweId": "CWE-693",
                    "description": "CWE-693 Protection Mechanism Failure"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T19:40:53.332Z"
            }
          }
        ],
        "cna": {
          "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
          "shortName": "mozilla",
          "dateUpdated": "2026-10-13T18:17:24.062Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-109783",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 338281,
  "published_at": "2026-10-13T12:29:36.256+00:00"
}