Review reviewHigh

CVE-2026-44698

home-assistant core, Companion app (iOS), Companion app (Android)

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...

CVSS: 8.3
EPSS: 0.14%
CISA KEV: Not listed
Published: 2026.05.29

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.14%

Technical severityCVSS 8.3

Vulnerability overview

Affected product and versions

Product: home-assistant core, Companion app (iOS), Companion app (Android)
Affected versions: >= < 2026.4.4, >= < 2026.4.1
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that home-assistant core, Companion app (iOS), Companion app (Android) and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
CWE: CWE-346, CWE-749, CWE-94, CWE-940