CVE-2026-84140
Received Received - Intake

DOM Navigation Site Isolation Bypass in Firefox

Publication date: 2026-09-01

Last updated on: 2026-09-01

Assigner: Mozilla Corporation

Description
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155 and Firefox ESR 153.2.

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Meta Information

Published
2026-09-01
Last Modified
2026-09-01
Generated
2026-09-01
AI Q&A
2026-09-01
EPSS Evaluated
N/A
NVD
CVE-2026-84140
EUVD
EUVD-2026-69088

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mozilla firefox to 155 (inc)
mozilla firefox_esr to 153.2 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a site isolation issue in the DOM Navigation component of Firefox. It was patched in Firefox 155 and Firefox ESR 153.2. Site isolation is a security feature that separates different websites to prevent malicious sites from accessing data from other sites.

Impact Analysis

An attacker could exploit this to access sensitive data from other sites you visit, such as login credentials or personal information. This could lead to identity theft, financial loss, or unauthorized access to accounts.

Mitigation Strategies

Update Firefox to version 155 or later and Firefox ESR to version 153.2 or later to address the site isolation issue in the DOM Navigation component.

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