CVE-2025-10859: firefox — Fix

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.

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CVSS v3.1 Score

4.0

MEDIUM

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

Weakness Type (CWE)

CWE-359 CWE-359

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 143.1.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-79/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1684624

Frequently Asked Questions

What is CVE-2025-10859? +

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. It has a CVSS v3.1 base score of 4.0 (MEDIUM).

How severe is CVE-2025-10859? +

CVE-2025-10859 has a CVSS v3.1 score of 4.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-10859? +

CVE-2025-10859 affects products from mozilla, specifically: firefox. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-10859? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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