Vulnerability · Published Sep 30, 2025 · Assigned by mozilla
CVE-2025-10859Data stored in cookies for non-HTML content while browsing Incognito could be viewed after closing private tabs
Medium 4.0
In plain English
A medium-severity security flaw in Firefox for iOS from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Severity (CVSS 3.1)4.0Medium
Exploit odds (30 days)0.1%top 98.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox for iOS | see references |
Weakness: CWE-359 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N