CVE-2025-10859

low-risk

Published 2025-09-30

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.

Do I need to act?

0.02% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 4.0/10 Medium

LOCAL / LOW complexity

Affected Products (1)

Firefox

Affected Vendors

Mozilla

References (2)

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

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

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low-risk

Severity 14/34 · Moderate

Exploitability 0/34 · Minimal

Exposure 5/34 · Minimal