CVE-2026-86853

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

08/09/2026

Last modified:

08/09/2026

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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L CVSS v3.1 Severity and Metrics:

Base Score: 4.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): Low

Base Score 3.x

4.30

Severity 3.x

MEDIUM

References to Advisories, Solutions, and Tools

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