CVE-2026-12304
Undergoing Analysis Undergoing Analysis - In Progress

Same-Origin Policy Bypass in Firefox

Publication date: 2026-06-16

Last updated on: 2026-06-16

Assigner: Mozilla Corporation

Description
Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-06-16
Last Modified
2026-06-16
Generated
2026-07-06
AI Q&A
2026-06-16
EPSS Evaluated
2026-07-05
NVD
CVE-2026-12304
EUVD
EUVD-2026-37095

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mozilla firefox 152
mozilla firefox_esr 140.12

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-346 The product does not properly verify that the source of data or communication is valid.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is a same-origin policy bypass in the Networking: Cookies 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 of this policy could allow unauthorized access to cookies across different origins.

The issue was addressed and fixed in Firefox version 152 and Firefox ESR 140.12.

Impact Analysis

By bypassing the same-origin policy in the cookies component, an attacker could potentially access or manipulate cookies from other origins without proper authorization. This could lead to unauthorized access to user sessions, personal data, or other sensitive information stored in cookies.

Mitigation Strategies

To mitigate this vulnerability, update Firefox to version 152 or later, or Firefox ESR to version 140.12 or later, where the issue has been fixed.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-12304. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart