CVE-2026-55644: Element X iOS: io.element.call deeplink allows attacker-controlled HTTPS origin and may grant mic/camera to that origin
Element X iOS is a Matrix iOS Client provided by Element. Element X iOS before version 26.05.0 fails to check the URL allowlist when parsing io.element.call://. If an attacker is able to trick the user into opening a maliciously crafted io.element.call:// URL, they are able to load an attacker-controlled origin inside the call screen's WKWebView which will be granted device microphone and camera permissions (provided the user has previously granted these permissions to Element X iOS). This issue has been patched in version 26.05.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Element X iOSto a version that resolves this vulnerability.Fixed in 26.05.0
Event History
Frequently Asked Questions
Who is exposed to this issue?
Users of Element X iOS versions before 26.05.0 are exposed if they have previously granted the app microphone and camera permissions and can be persuaded to open a malicious io.element.call:// URL.
What does an attacker need to exploit it?
The attacker needs to craft a malicious io.element.call:// URL and trick the user into opening it. No attacker authentication or privileges are required, but user interaction is required.
What can an attacker access after successful exploitation?
A successful exploit can load an attacker-controlled HTTPS origin in the call screen WKWebView. That origin may receive microphone and camera permissions already granted to Element X iOS.
What should teams do if they cannot patch immediately?
The available data identifies updating to version 26.05.0 as the patch. Until then, users should avoid opening untrusted io.element.call:// links; the issue also depends on Element X iOS already having microphone and camera permissions.