Medium · 4.3 CVE-2026-86853 EUVD-2026-72875GHSA-4c3m-8r8c-3rf3

Repeated external URL scheme launches could potentially cause a denial of service in Firefox for iOS

Published Sep 8, 2026 · Updated Sep 8, 2026 · Assigned by mozilla

Vendor: Mozilla Product: Firefox for iOS Platform: iOS Category: Browsers

Description

A malicious webpage could repeatedly trigger external URL schemes, causing system prompts or external application launches. This could make Firefox for iOS temporarily unusable until the page is closed. This vulnerability was fixed in Firefox for iOS 155.1.

Affected products

Vendor	Product	Affected	Fixed
Mozilla	Firefox for iOS	—	155.1

Advisories 1

WID-SEC-2026-3274 Mozilla Firefox für iOS: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Sep 8, 2026

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1847631
https://www.mozilla.org/security/advisories/mfsa2026-89/