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CVE-2026-84137 Details

Description

Spoofing issue in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:4.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CNA: CISA-ADPCVSS-B:9.8 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://bugzilla.mozilla.org/show_bug.cgi?id=2051146	[email protected]	Issue TrackingPermissions Required
https://www.mozilla.org/security/advisories/mfsa2026-82/	[email protected]	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-85/	[email protected]	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-86/	[email protected]	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-88/	[email protected]	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-346	Origin Validation Error	[email protected]
CWE-451	User Interface (UI) Misrepresentation of Critical Information	CISA-ADP

Affected Products

Product	Versions
mozilla firefox	< 153.2.0 >= 154.0.0, < 155.0.0
CPE cpe:2.3:a:mozilla:firefox:::::::: Remediation No remediation found in references.
mozilla thunderbird	< 153.2.0 >= 154.0, < 155.0
CPE cpe:2.3:a:mozilla:thunderbird:::::::: Remediation No remediation found in references.

Change History

4 change records found show changes

Date	Action	Recorded By
Sep 3, 2026	CVE Modified	CISA-ADP
Sep 3, 2026	Initial Analysis	[email protected]
Sep 1, 2026	CVE Modified	[email protected]
Sep 1, 2026	New CVE Received	[email protected]