CVE-2026-44698

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

HIGH
8.3
CVSS Score
Published: May 29, 2026 at 01:32 PM UTC
Updated: July 21, 2026 at 01:39 PM UTC
2 products affected across 1 vendorHome AssistantHome Assistant Companion

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Severity
HIGH8.3
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2026.4.4
Affected range stops below 2026.4.4, so it looks safe — our inference, not a vendor statement
v < 2026.4.1v < 2026.4.4
Affected range stops below 2026.4.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 2026.4.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.3HIGHGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-94CWE-346CWE-749CWE-940

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