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

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact total

Affected Vendors & Products

Vendors Products
Mozilla
  • Firefox

No data.

No data.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=2047240 cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-16396 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-16396 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-68/ cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-70/ cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-70/#CVE-2026-16396 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-71/ cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-72/ cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-72/#CVE-2026-16396 cve-icon
History

Fri, 24 Jul 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

 cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Fri, 24 Jul 2026 00:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-266
References
Metrics threat_severity

None

 threat_severity

Moderate

Wed, 22 Jul 2026 20:00:00 +0000

Type Values Removed Values Added
Description Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13. Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
References

Wed, 22 Jul 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-269
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Wed, 22 Jul 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 21 Jul 2026 12:45:00 +0000

Type Values Removed Values Added
Description Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13.
Title Privilege escalation in WebExtensions
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published: 2026-07-21T12:38:09.831Z

Updated: 2026-07-24T20:13:53.093Z

Reserved: 2026-07-20T21:57:23.712Z

Link: CVE-2026-16396

cve-icon Vulnrichment

Updated: 2026-07-22T18:02:15.708Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-21T12:38:09Z

Links: CVE-2026-16396 - Bugzilla