CVE-2026-109434

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.

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://www.fenrir-inc.com/jp/news/2026/10/15/sleipnir-mobile-for-android-3-9-0/
https://www.vulncheck.com/advisories/sleipnir-browser-fullscreen-address-bar-spoofing

Configurations

No configuration.

History

19 Oct 2026, 19:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-19 19:17

Updated : 2026-10-19 21:14

NVD link : CVE-2026-109434

Mitre link : CVE-2026-109434

CVE.ORG link : CVE-2026-109434

JSON object : View

Products Affected

No product.

CWE

CWE-451

User Interface (UI) Misrepresentation of Critical Information

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