CVE-2026-16399: Vulnerability in Mozilla Firefox
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 153.
AI Analysis
Technical Summary
CVE-2026-16399 is a site isolation issue affecting the DOM: Navigation component in Mozilla Firefox. Site isolation is a security feature that enforces process separation between different web origins to prevent cross-origin attacks. This vulnerability could undermine that isolation, potentially allowing unauthorized access or interaction between web origins. Mozilla fixed this vulnerability in Firefox 153. The advisory categorizes the impact as moderate and no active exploitation is known.
Potential Impact
The vulnerability could reduce the effectiveness of site isolation in Firefox, potentially allowing cross-origin interactions that are normally prevented. This may lead to unauthorized access to web content or data from other origins within the browser context. However, the impact is rated moderate by Mozilla, and no active exploitation has been observed.
Mitigation Recommendations
Mozilla has fixed this vulnerability in Firefox version 153. Users and administrators should update to Firefox 153 or later to remediate this issue. Patch status is confirmed by the vendor advisory. No additional mitigation actions are required beyond applying the official update.
CVE-2026-16399: Vulnerability in Mozilla Firefox
Description
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 153.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-16399 is a site isolation issue affecting the DOM: Navigation component in Mozilla Firefox. Site isolation is a security feature that enforces process separation between different web origins to prevent cross-origin attacks. This vulnerability could undermine that isolation, potentially allowing unauthorized access or interaction between web origins. Mozilla fixed this vulnerability in Firefox 153. The advisory categorizes the impact as moderate and no active exploitation is known.
Potential Impact
The vulnerability could reduce the effectiveness of site isolation in Firefox, potentially allowing cross-origin interactions that are normally prevented. This may lead to unauthorized access to web content or data from other origins within the browser context. However, the impact is rated moderate by Mozilla, and no active exploitation has been observed.
Mitigation Recommendations
Mozilla has fixed this vulnerability in Firefox version 153. Users and administrators should update to Firefox 153 or later to remediate this issue. Patch status is confirmed by the vendor advisory. No additional mitigation actions are required beyond applying the official update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-07-20T21:57:29.336Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-68/","vendor":"Mozilla"}]
Threat ID: 6a5f6cc22a4a8d5989262946
Added to database: 07/21/2026, 12:57:38 UTC
Last enriched: 07/21/2026, 13:14:19 UTC
Last updated: 07/21/2026, 21:19:23 UTC
Views: 4
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