CVE Catalog

CVE-2026-44698

HighCVSS 8.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.14%

3th percentile - higher than 3% of all known CVEs

Summary

Home Assistant Companion apps for iOS and Android expose a JavaScript bridge to the in-app WebView that is vulnerable to cross-origin iframe attacks. This flaw allows arbitrary JavaScript execution in the main-frame origin of the Home Assistant frontend and exfiltration of the signed-in user's access token.

Risk Assessment

An attacker can hijack the user's session, gaining full access to their Home Assistant instance, including control over devices and private data.

Recommendation

Immediately update the Home Assistant Companion app on iOS to version 2026.4.1 or later, and on Android to version 2026.4.4 or later.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS