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CVE-2026-44698

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

Published: May 29, 2026Updated: May 29, 2026 Sources: CVE List NVD
8.3CVSS
HIGH

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.

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

CVSS Vector Breakdown

AV:NAC:HPR:NUI:RS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High

Weaknesses

Affected Products

core
home-assistant
Companion app (iOS)
Home Assistant
Companion app (Android)
Home Assistant

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

Timeline

Published
May 29, 2026
Last Updated
May 29, 2026

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