CVE-2026-86853

MEDIUM 4.3

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

CVSS Score

4.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

Vendor	mozilla
Product	firefox for ios
Ecosystems	Browser JavaScript
Industries	Technology
Published	Sep 8, 2026
Last Updated	Sep 8, 2026

Stay Ahead of the Next One

Get instant alerts for mozilla firefox for ios

Be the first to know when new medium vulnerabilities affecting mozilla firefox for ios are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

Affected Versions

Mozilla / Firefox for iOS

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Amit Gajbhare