CVE-2025-10859

Name: CVE-2025-10859
Creator: NVD / NIST
Published: 2025-09-30T13:15:48.55+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4/10EPSS 0.11%

Last modified Jun 17, 2026

CVE-2025-10859 is a medium-severity vulnerability rated 4/10 on the CVSS scale. 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.. EPSS estimates a 0.11% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.11%

1.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-359

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 143.1.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1684624Issue Tracking, Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-79/Vendor Advisory

Timeline

Published: Sep 30, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-10859?

How severe is CVE-2025-10859?

CVE-2025-10859 has a CVSS score of 4/10 (MEDIUM severity). The EPSS model estimates a 0.11% probability of exploitation in the next 30 days.

How do I fix CVE-2025-10859?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-10859?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST