Description
Home Assistant is open source home automation software that puts local control and privacy first. Prior to 2026.4.1 for iOS and 2026.4.4 for Android, he Home Assistant Companion apps for Android and iOS expose a JavaScript bridge to the in-app WebView window.externalApp on Android and webkit.messageHandlers.getExternalAuth (alongside revokeExternalAuth and externalBus) on iOS. Two flaws expose the bridge to all frames (including cross-origin iframes) and unsanitized interpolation of the JavaScript callback identifier allows a cross-origin iframe rendered inside the Companion app to execute arbitrary JavaScript in the Home Assistant frontend's main-frame origin and exfiltrate the signed-in user's access token. This vulnerability is fixed in 2026.4.1 for iOS and 2026.4.4 for Android.
Problem types
CWE-94: Improper Control of Generation of Code ('Code Injection')
CWE-346: Origin Validation Error
CWE-749: Exposed Dangerous Method or Function
CWE-940: Improper Verification of Source of a Communication Channel
Product status
References
github.com/...t/core/security/advisories/GHSA-7jp2-p2fw-mgvf