CVE-2025-6425: Vulnerability in Mozilla Firefox
An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
AI Analysis
Technical Summary
The vulnerability CVE-2025-6425 involves the WebCompat WebExtension in Firefox exposing a persistent UUID that uniquely identifies the browser instance. This UUID remains consistent across container tabs and normal/private browsing modes but resets with different Firefox profiles. An attacker enumerating resources from the WebCompat extension could retrieve this UUID, potentially allowing tracking of the browser across browsing sessions. The issue was addressed and fixed in Firefox 140 and related ESR and Thunderbird versions as noted in Mozilla's security advisories MFSA 2025-51 and 2025-52.
Potential Impact
The impact is moderate and limited to privacy concerns. An attacker could use the exposed persistent UUID to track a user's browser across container tabs and normal/private browsing modes, potentially undermining user privacy. There is no indication of confidentiality, integrity, or availability compromise beyond this tracking capability. No known active exploitation has been reported.
Mitigation Recommendations
This vulnerability has been fixed by Mozilla in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation actions are required as the fix is official and available.
CVE-2025-6425: Vulnerability in Mozilla Firefox
Description
An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2025-6425 involves the WebCompat WebExtension in Firefox exposing a persistent UUID that uniquely identifies the browser instance. This UUID remains consistent across container tabs and normal/private browsing modes but resets with different Firefox profiles. An attacker enumerating resources from the WebCompat extension could retrieve this UUID, potentially allowing tracking of the browser across browsing sessions. The issue was addressed and fixed in Firefox 140 and related ESR and Thunderbird versions as noted in Mozilla's security advisories MFSA 2025-51 and 2025-52.
Potential Impact
The impact is moderate and limited to privacy concerns. An attacker could use the exposed persistent UUID to track a user's browser across container tabs and normal/private browsing modes, potentially undermining user privacy. There is no indication of confidentiality, integrity, or availability compromise beyond this tracking capability. No known active exploitation has been reported.
Mitigation Recommendations
This vulnerability has been fixed by Mozilla in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation actions are required as the fix is official and available.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- mozilla
- Date Reserved
- 2025-06-20T14:51:28.050Z
- Cvss Version
- null
- State
- PUBLISHED
Threat ID: 685aa0274dc24046c1dc5a91
Added to database: 6/24/2025, 12:55:03 PM
Last enriched: 4/14/2026, 11:51:28 AM
Last updated: 5/8/2026, 12:47:48 PM
Views: 95
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