CVE-2026-44698: Home Assistant: Cross-origin iframe access token exfiltration via WebView JS bridge callback injection
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Home Assistant Companion iOS appto a version that resolves this vulnerability.Fixed in 2026.4.1 - Upgrade
Upgrade
Home Assistant Companion Android appto a version that resolves this vulnerability.Fixed in 2026.4.4
Event History
Frequently Asked Questions
What is the severity of CVE-2026-44698?
The severity of CVE-2026-44698 is high with a score of 8.3.
How do I fix CVE-2026-44698?
To fix CVE-2026-44698, update to Home Assistant Companion apps version 2026.4.1 for iOS and 2026.4.4 for Android.
What applications are affected by CVE-2026-44698?
CVE-2026-44698 affects the Home Assistant Companion apps for iOS and Android.
What type of vulnerability is CVE-2026-44698?
CVE-2026-44698 is classified as a code injection vulnerability.
What is the potential impact of CVE-2026-44698?
The potential impact of CVE-2026-44698 includes cross-origin iframe access token exfiltration.