Medium · 4.0 CVE-2025-10859 EUVD-2025-31731GHSA-q64v-9mh2-3xcq

Data stored in cookies for non-HTML content while browsing Incognito could be viewed after closing private tabs

Published Sep 30, 2025 · Updated Apr 13, 2026 · Assigned by mozilla

Vendor: Mozilla Product: Firefox for iOS Platform: iOS Category: Browsers

Description

Cookie storage for non-HTML temporary documents was being shared incorrectly with normal browsing content, allowing information from private tabs to escape Incognito mode even after the user closed all tabs. This vulnerability was fixed in Firefox for iOS 143.1.

Affected products

Vendor	Product	Affected	Fixed
Mozilla	Firefox for iOS	—	143.1

Advisories 1

WID-SEC-2025-2168 Mozilla Firefox: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 5, 2025

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1684624
https://www.mozilla.org/security/advisories/mfsa2025-79/