CVE-2026-86853
MEDIUM 4.3 ALL-YEARSA 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.
LIMITED SIGNALS
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 19th percentile
○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no
Impact if exploited
4.3CVSS 3.1 · MEDIUM · ADP
- ConfidentialityNone
- IntegrityNone
- AvailabilityLow
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.
Weakness (CWE)
- CWE-451: User Interface (UI) Misrepresentation of Critical Information
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Mozilla | Firefox Mobile | < 155.1 |
All CVSS metrics
- MEDIUM 4.3 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L - MEDIUM 4.3 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L