CVE-2026-86853
Medium
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.
SeverityMedium
CVSS4.3
Exploit probability—
Product
Mozilla Firefox Mobile
PublishedSep 8, 2026
First seenSep 8, 2026
Weakness typeCWE-451CWE-451
How to fix
Update
- mozilla firefox_mobile155.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox_mobile | v < 155.1 | 155.1 |
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