CVE-2026-44698

Home Assistant: Cross-origin iframe access token exfiltration via WebView JS bridge callback injection

Published May 29, 2026 CVSS 3.1 · 8.3 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Home-assistant
Home-assistant companion App
Home-assistant core
Vendors & Products Home-assistant
Home-assistant companion App
Home-assistant core
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Home Assistant: Cross-origin iframe access token exfiltration via WebView JS bridge callback injection
Weaknesses CWE-346
CWE-749
CWE-94
CWE-940
References
Metrics cvssV3_1

{'score': 8.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H'}

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 29, 2026, 1:58 PM
Reserved
May 7, 2026, 5:07 PM
Status
Awaiting Analysis
Published
May 29, 2026, 2:16 PM
Modified
Jul 21, 2026, 12:10 PM