{"id":"CVE-2026-109434","title":"Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofing","summary":"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 p…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","cvssSource":"cna","cwe":["CWE-451"],"vendor":"Fenrir","product":"Sleipnir Mobile for Android","affected":["sleipnir_mobile_for_android < 3.9.0"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-19T18:36:32.278770Z"},"published":"2026-10-19","updated":"2026-10-19","sourceUpdated":"2026-10-19T18:36:45.158Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-109434","references":[{"url":"https://www.fenrir-inc.com/jp/news/2026/10/15/sleipnir-mobile-for-android-3-9-0/","label":"Vendor Advisory"},{"url":"https://www.vulncheck.com/advisories/sleipnir-browser-fullscreen-address-bar-spoofing","label":"VulnCheck Advisory: Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofing"}],"tags":["cve.org"],"ingestedAt":"2026-10-19T18:35:50.141Z","slug":"CVE-2026-109434","body":"## Overview\n\nFenrir 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.\n\n## Affected\n\n- `sleipnir_mobile_for_android < 3.9.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}