CVE-2026-8948

Analyzed Analyzed - Analysis Complete

Same-origin policy bypass in Firefox DOM Networking

Publication date: 2026-05-19

Last updated on: 2026-05-20

Assigner: Mozilla Corporation

Description

Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVSS Scores

EPSS Scores

Probability:
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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-2026-8948

EUVD

EUVD-2026-30900

Affected Vendors & Products

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

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-942	The product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.

Attack-Flow Graph

Executive Summary

This vulnerability is a same-origin policy bypass in the DOM Networking component of Mozilla Firefox. The same-origin policy is a critical security mechanism that restricts how documents or scripts loaded from one origin can interact with resources from another origin. A bypass means that this restriction can be circumvented, potentially allowing malicious scripts to access or manipulate data from other origins.

This issue was fixed in Firefox version 151.

Impact Analysis

By bypassing the same-origin policy, an attacker could potentially access sensitive information or perform unauthorized actions by exploiting the DOM Networking component. This could lead to data leakage, unauthorized data manipulation, or other security breaches within the browser environment.

Mitigation Strategies

The vulnerability was fixed in Firefox 151. To mitigate this vulnerability, you should update your Firefox browser to version 151 or later.

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