Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker's computer into the target account. This vulnerability was fixed in Firefox for iOS 142 and Focus for iOS 142.
Conclusion & alert: CVE-2025-55031 is rated Moderate Risk (50.1/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.39%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.06% | 0.39% | +0.33% |
| 2 | 2025-08-25 | 0.02% | 0.06% | +0.04% |
| 3 | 2025-08-20 | — | 0.02% | — |
Full EPSS history (3 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2025-55031: 1 source package rows (firefox); 115 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 115. | https://security.alpinelinux.org/vuln/CVE-2025-55031 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | firefox | < 142.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:iphone_os:*:* |
| mozilla | firefox_focus | < 142.0 | cpe:2.3:a:mozilla:firefox_focus:*:*:*:*:*:iphone_os:*:* |
| URL | Tags |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1979499 | Issue Tracking Permissions Required |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1979804 | Issue Tracking Permissions Required |
| https://www.mozilla.org/security/advisories/mfsa2025-68/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-69/ | Vendor Advisory |