CVE-2026-109434

medium

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.

References

https://www.vulncheck.com/advisories/sleipnir-browser-fullscreen-address-bar-spoofing

https://www.fenrir-inc.com/jp/news/2026/10/15/sleipnir-mobile-for-android-3-9-0/

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-104568

Details

Source: Mitre, NVD

Published: 2026-10-19

Updated: 2026-10-19

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 4.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Severity: Medium

CVSS v4

Base Score: 5.1

Vector: 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

Severity: Medium

EPSS

EPSS: 0.00303