Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

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
  • Thunderbird

Configuration 1 [-]

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

No data.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=2031064 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-8955 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-8955 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-46/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/#CVE-2026-8955 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-50/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-51/ cve-icon cve-icon
History

Fri, 22 May 2026 00:15:00 +0000

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

None

 threat_severity

Moderate

Wed, 20 May 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, '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'}

Wed, 20 May 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird

Tue, 19 May 2026 17:45:00 +0000

Type Values Removed Values Added
Description Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11. Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
References

Tue, 19 May 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Tue, 19 May 2026 16:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Tue, 19 May 2026 15:45:00 +0000

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

Tue, 19 May 2026 15:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-269
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

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

Tue, 19 May 2026 13:45:00 +0000

Type Values Removed Values Added
Description Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
Title Privilege escalation in the DOM: Workers component
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published: 2026-05-19T12:29:49.649Z

Updated: 2026-05-20T15:37:35.207Z

Reserved: 2026-05-19T12:29:48.978Z

Link: CVE-2026-8955

cve-icon Vulnrichment

Updated: 2026-05-19T14:20:14.577Z

cve-icon NVD

Status : Modified

Published: 2026-05-19T14:16:51.820

Modified: 2026-05-20T17:16:29.980

Link: CVE-2026-8955

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-05-19T12:29:49Z

Links: CVE-2026-8955 - Bugzilla