TI-2026-59376 Aliases CVE-2026-86853 GHSA-4c3m-8r8c-3rf3

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

LOW 20CWE-451Published 2026-09-08 · Updated 2026-09-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Spoofing
Confidentiality · integrity · availability: None · None · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-451.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00278 20th percentileScored 2026-11-07

Fix Fixed Firefox for iOS (Mozilla): 155.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Mozilla	Firefox for iOS	—	155.1	Patch available	CNA

Firefox for iOS VendorMozilla Affected — Fixed in 155.1 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:mozilla:firefox_mobile::::::iphone_os::*	before 155.1	Vulnerable	Mozilla

cpe:2.3:a:mozilla:firefox_mobile:*:*:*:*:*:iphone_os:*:* Versions before 155.1 Vulnerable ·Mozilla

Remediation

Fix · CNA Firefox for iOS (Mozilla) Fixed in 155.1

Timeline

2026-10-02 Threatist record created from CVE-2026-86853
2026-10-03 Alias added: GHSA-4c3m-8r8c-3rf3

References

Advisory 1

https://www.mozilla.org/security/advisories/mfsa2026-89/

Other 1

https://bugzilla.mozilla.org/show_bug.cgi?id=1847631

TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
TI-2022-09831 Use after free in Mozilla Firefox KEVCVSS 3.1HIGH 8.8
TI-2023-13905 Race condition in Mozilla Firefox for Android CVSS 3.1HIGH 7.5
TI-2023-13916 A wrong lowering instruction in the ARM64 Ion compiler resulted in a wrong optimization… CVSS 3.1MEDIUM 6.5
TI-2023-13903 Following a Garbage Collector compaction, weak maps may have been accessed before they… CVSS 3.1MEDIUM 6.5
TI-2022-13642 Information disclosure in Mozilla Firefox for iOS CVSS 3.1MEDIUM 6.5

See all 86 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences