CVE-2026-109434
Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofing
- State
- Published
- Severity
- 5.1 Medium
- Published
- Oct 19, 2026
- Updated
- Oct 19, 2026
- Reserved
- Oct 12, 2026
Description
Fenrir Sleipnir Browser for Android before 3.9.0 contains a UI spoofing vulnerability that allows remote attackers to impersonate the browser's trusted address bar by entering fullscreen mode via the Fullscreen API without displaying a persistent notification or trusted-origin indicator. Attackers can render a counterfeit address bar showing a trusted origin over attacker-controlled content after a single user tap, enabling credential harvesting, malware delivery, or social engineering through fake login, update, or payment pages.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.1 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 4.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N | VulnCheck |
Weaknesses
- CWE-451 User Interface (UI) Misrepresentation of Critical Information
Affected Products
| Product | Versions |
|---|---|
Sleipnir Mobile for AndroidFenrir |
|
References
- Vendor Advisoryvendor-advisorypatch
- VulnCheck Advisory: Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofingthird-party-advisory
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