CVE-2025-10859
Data stored in cookies for non-HTML content while browsing Incognito could be viewed after closing private tabs
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Data stored in cookies for non-HTML content while browsing Incognito could be viewed after closing private tabs
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.
- Record
CVE-2025-10859- CVSS 3.1
- 4.0 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-359
- Updated
- 2026-11-02
EUVDEUVD-2025-31731
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.
- Record
EUVD-2025-31731- CVSS 3.1
- 4.0 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-q64v-9mh2-3xcq
Cookie storage for non-HTML temporary documents was being shared incorrectly with normal browsing...
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 affects Firefox for iOS < 143.1.
- Record
GHSA-q64v-9mh2-3xcq- CVSS 3.1
- 4.0 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-359
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-10859- CVSS 3.1
- 4.0 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-359
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-10859 is a medium vulnerability (CVSS 4.0) in Mozilla Firefox, published September 30, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.12%, the 1st percentile. No source names a fixed version.