CVE-2026-16381
Received Received - Intake

Same-origin policy bypass in Firefox

Publication date: 2026-07-21

Last updated on: 2026-07-21

Assigner: Mozilla Corporation

Description
Same-origin policy bypass in the Networking: DNS component. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13.

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Meta Information

Published
2026-07-21
Last Modified
2026-07-21
Generated
2026-07-21
AI Q&A
2026-07-21
EPSS Evaluated
N/A
NVD
CVE-2026-16381
EUVD
EUVD-2026-46218

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
mozilla firefox to 153 (inc)
mozilla firefox_esr to 140.13 (inc)
mozilla firefox 153
mozilla firefox_esr 140.13

Helpful Resources

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 same-origin policy bypass in the Networking: DNS component of Firefox and Firefox ESR. The same-origin policy is a security feature that prevents scripts from one website from accessing data from another website unless they share the same origin. A bypass means an attacker could potentially access sensitive data across different origins.

Impact Analysis

If exploited, this vulnerability could allow an attacker to bypass security restrictions and access data from different websites or applications that should be isolated. This may lead to unauthorized access to sensitive information such as login credentials, personal data, or financial details.

Compliance Impact

This vulnerability could lead to unauthorized data access, which may violate compliance requirements under GDPR (data protection) and HIPAA (health information privacy). Organizations using affected Firefox versions may face legal penalties, reputational damage, and increased scrutiny from regulators.

Mitigation Strategies

Update Firefox to version 153 or later and Firefox ESR to version 140.13 or later to address the same-origin policy bypass in the Networking: DNS component.

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