CVE-2026-109750

Deferred Deferred - Pending Action

DOM Isolation Bypass in Firefox

Publication date: 2026-10-13

Last updated on: 2026-10-19

Assigner: Mozilla Corporation

Description

Site isolation issue in the DOM: Web Authentication component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-19

Generated

2026-11-08

AI Q&A

2026-10-13

EPSS Evaluated

2026-11-07

NVD

CVE-2026-109750

EUVD

EUVD-2026-98512

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	158

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-862	The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

Executive Summary

This is a site isolation issue in the DOM Web Authentication component of Firefox. It allows potential unauthorized access between different sites due to improper separation of web content. The vulnerability was addressed in Firefox version 158.

Impact Analysis

An attacker could exploit this to access sensitive data from one site while you are logged into another site. This may lead to theft of cookies, session tokens, or other credentials, potentially allowing account takeover or unauthorized actions on your behalf.

Mitigation Strategies

Update Firefox to version 158 or later to address the DOM: Web Authentication site isolation issue.

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