CVE-2026-44698CWE-346CWE-749CWE-94CWE-940

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

High · published May 29, 2026

CVSS v3.1
8.3
EPSS
0%
Percentile
5.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.3 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00165 · 5.4th percentile
Weaknesses
CWE-346 · Origin Validation Error; CWE-749 · Exposed Dangerous Method or Function; CWE-94 · Improper Control of Generation of Code ('Code Injection'); CWE-940 · Improper Verification of Source of a Communication Channel
Published
2026-05-29T13:32Z
EPSS history
Timeline
  • 29 MAY 13:32Z
    Home Assistant: Cross-origin iframe access token exfiltration via WebView JS bridge callback injection
    cvelistv5