CVE-2026-86853 | BDVDB-2026-370482 Detail

MozillaFirefox for iOS

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#

Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact low. Attack vector: network.

Weaknesses#

CWE-451 User Interface (UI) Misrepresentation of Critical Information

References#

Exploit#

No public exploit known

History#

Version 12026-09-08Record published in the CVE List.

Published

Published: 2026-09-08
Last modified: 2026-09-08

Vendor information

Vendor: Mozilla
Product: Firefox for iOS

All Mozilla vulnerabilities

Score

4.3 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 20.3.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
Not stated
Fixed
155.1

Scoring System

CVSS v4.0

Not available

CVSS v3.1

4.3 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity	None
Availability	Low

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).