CVE-2026-8955

Modified Modified - Updated After Analysis

Privilege Escalation in Firefox DOM Workers

Publication date: 2026-05-19

Last updated on: 2026-05-20

Assigner: Mozilla Corporation

Description

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

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-05-19

Last Modified

2026-05-20

Generated

2026-06-30

AI Q&A

2026-05-19

EPSS Evaluated

2026-06-28

NVD

CVE-2026-8955

EUVD

EUVD-2026-30905

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 151.0.0 (exc)
mozilla	firefox	to 140.11.0 (exc)
mozilla	thunderbird	to 151.0.0 (exc)
mozilla	thunderbird	to 140.11 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-269	The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Attack-Flow Graph

Executive Summary

This vulnerability is a privilege escalation issue in the DOM: Workers component of Mozilla Firefox. It allows an attacker to gain higher privileges than intended within the browser environment. The issue was addressed and fixed in Firefox version 151 and Firefox ESR 140.11.

Impact Analysis

The vulnerability could allow an attacker to escalate their privileges within the browser, potentially enabling them to execute actions or access data that should be restricted. This could lead to unauthorized access or manipulation of browser processes or user data.

Mitigation Strategies

To mitigate this privilege escalation vulnerability in the DOM: Workers component, you should update your Firefox browsers to version 151 or later, and Firefox ESR to version 140.11 or later.

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