CVE-2026-109434
Received Received - Intake

Fenrir Sleipnir Browser Android UI Spoofing

Publication date: 2026-10-19

Last updated on: 2026-10-19

Assigner: VulnCheck

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-19
Last Modified
2026-10-19
Generated
2026-10-20
AI Q&A
2026-10-19
EPSS Evaluated
N/A
NVD
CVE-2026-109434
EUVD
EUVD-2026-104568

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Fenrir Sleipnir Mobile for Android 0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-451 The user interface (UI) does not properly represent critical information to the user, allowing the information - or its source - to be obscured or spoofed. This is often a component in phishing attacks.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is a UI spoofing issue in Fenrir Sleipnir Browser for Android before version 3.9.0. Attackers can exploit the Fullscreen API to display a fake address bar that appears to show a trusted website URL. The spoofed bar overlays malicious content, tricking users into believing they are on a legitimate site. This requires only a single user tap to activate and can be used for phishing, credential theft, or malware delivery.

Detection Guidance

Detecting this vulnerability requires checking the installed version of Sleipnir Browser for Android. If the version is below 3.9.0, the system is vulnerable. No specific network commands are provided in the context, but users should verify the app version in system settings or Google Play Store.

Impact Analysis

This vulnerability can lead to phishing attacks where users enter login credentials or personal information on fake pages. It may also enable malware distribution through fake update or payment prompts. Users might unknowingly trust the spoofed interface and fall victim to social engineering attacks, risking data theft or financial loss.

Compliance Impact

This vulnerability could undermine compliance with GDPR and HIPAA by enabling phishing attacks that trick users into revealing sensitive personal or health data through fake login pages. Attackers could impersonate legitimate domains in the spoofed address bar, potentially violating data protection requirements for secure authentication and user consent.

Mitigation Strategies

Update Sleipnir Browser for Android to version 3.9.0 or later immediately. This version includes security enhancements that display the current domain and instructions for exiting full-screen mode, reducing the risk of UI spoofing attacks.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-109434. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart