CVE-2026-86853
MEDIUMCVSS 4.3/10EPSS 0.30%
Last modified
CVE-2026-86853 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.30% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox Mobile | < 155.1 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1847631Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-89/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-86853?
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.
How severe is CVE-2026-86853?
CVE-2026-86853 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.
How do I fix CVE-2026-86853?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-86853?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST