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CVE-2026-16396

Full vulnerability record from the local CVENow database.

Description

Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Severity
HIGH
CVSS score
8.8 (v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-07-21 13:17:14.853000
Last modified
2026-10-24 20:10:00.137000
View original CVE JSON
{
  "id": "CVE-2026-16396",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-21T13:17:14.853",
  "lastModified": "2026-10-24T20:10:00.137",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13."
    },
    {
      "lang": "es",
      "value": "Escalada de privilegios en WebExtensions. Esta vulnerabilidad fue corregida en Firefox 153, Firefox ESR 140.13, Thunderbird 153 y Thunderbird 140.13."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "version": "140.13",
              "lessThanOrEqual": "140.*",
              "versionType": "rpm",
              "status": "unaffected"
            },
            {
              "version": "153",
              "lessThanOrEqual": "*",
              "versionType": "rpm",
              "status": "unaffected"
            }
          ]
        },
        {
          "vendor": "Mozilla",
          "product": "Thunderbird",
          "versions": [
            {
              "version": "140.13",
              "lessThanOrEqual": "140.*",
              "versionType": "rpm",
              "status": "unaffected"
            },
            {
              "version": "153",
              "lessThanOrEqual": "*",
              "versionType": "rpm",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "REQUIRED",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-24T03:55:32.498630Z",
          "id": "CVE-2026-16396",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-269"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*",
              "versionEndExcluding": "140.13.0",
              "matchCriteriaId": "0D089F1A-9B89-4584-B58B-046555D9560E"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*",
              "versionEndExcluding": "153.0.0",
              "matchCriteriaId": "5DB4AF59-87C2-4FC4-896D-02879D6F8E6B"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
              "versionEndExcluding": "140.13.0",
              "matchCriteriaId": "9F5CEA4A-31D8-46F6-B259-0DFF56BD8F1D"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "141.0",
              "versionEndExcluding": "153.0",
              "matchCriteriaId": "B9C46740-CFEC-4FBB-8461-46E26518EE59"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2047240",
      "source": "[email protected]",
      "tags": [
        "Permissions Required"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-68/",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-70/",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-71/",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-72/",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}