CVE-2025-54143: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Sandboxed iframes on webpages could potentially allow downloads to the device, bypassing the expected sandbox restrictions declared on the parent page. This vulnerability was fixed in Firefox for iOS 141.

Affected products

• Mozilla Firefox: before 141.0 (fixed in 141.0)

Published 2025-08-19. Last modified 2026-10-05.