CVE-2026-92216: a2ui-project a2ui Open Redirect Vulnerability

CVE-2026-92216 Overview

CVE-2026-92216 is an open redirect vulnerability in the a2ui-project a2ui framework through version 0.10.7. The flaw resides in the openUrl function within renderers/web_core/src/v0_9/rendering/generic-binder.ts, part of the Binder component. Attackers can manipulate URL parameters to redirect users to arbitrary external destinations. The issue is exploitable remotely and requires user interaction. The vulnerability is classified under CWE-601: URL Redirection to Untrusted Site. The project maintainers were notified through an issue report but have not yet responded, leaving the flaw unpatched at the time of publication.

Critical Impact

Attackers can craft malicious links that appear to originate from a trusted a2ui-hosted application, then redirect victims to phishing or malware-hosting sites.

Affected Products

• a2ui-project a2ui versions up to and including 0.10.7
• Applications embedding the web_core renderer (v0_9) Binder component
• Downstream projects consuming the vulnerable generic-binder.ts module

Discovery Timeline

• 2026-09-16 - CVE-2026-92216 published to NVD
• 2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-92216

Vulnerability Analysis

The vulnerability exists in the openUrl function of generic-binder.ts within the web_core renderer. The function accepts a URL parameter and navigates the browser to it without validating that the destination points to a trusted origin. Because the a2ui framework binds UI elements to backend data, attacker-controlled input flowing into the Binder can drive the redirect. An attacker who controls any data source rendered through the Binder can supply an arbitrary URL that the client follows on user action.

Open redirects [CWE-601] are commonly chained with phishing campaigns. Victims see a legitimate a2ui-hosted domain in the initial link and trust the destination, which increases click-through and credential-harvest success rates. The flaw can also bypass domain-based allowlists used by security gateways that trust the origin host.

Root Cause

The root cause is missing validation of the destination URL passed to openUrl. The function does not verify scheme, host, or membership in an allowlist before invoking navigation. Any string reachable through data binding is treated as a safe redirect target.

Attack Vector

Exploitation is remote and requires user interaction, typically a click on an attacker-influenced UI element. An attacker crafts a payload that binds a malicious URL into a component rendered by the vulnerable Binder. When the user activates the element, the browser is redirected to the attacker's chosen destination. No authentication is required to deliver the malicious binding when the application exposes user-influenced data to the renderer.

Detailed technical information is available in the VulDB entry for CVE-2026-92216 and the upstream GitHub issue #2296.

Detection Methods for CVE-2026-92216

Indicators of Compromise

• Outbound HTTP requests from application users to external domains immediately after loading an a2ui-rendered page
• Web server or CDN logs showing referrer headers from a2ui application paths pointing to untrusted destinations
• User reports of unexpected navigation away from a trusted a2ui-hosted application

Detection Strategies

• Static analysis of application bundles for calls to openUrl in generic-binder.ts where the URL argument originates from untrusted data sources
• Runtime interception of window.location and window.open calls to log destination hostnames against an allowlist
• Content Security Policy (CSP) reporting endpoints configured with form-action and navigate-to directives to capture policy violations

Monitoring Recommendations

• Ingest web proxy and browser telemetry into a centralized data lake and alert on redirects from a2ui domains to newly registered or low-reputation domains
• Correlate phishing report submissions with URLs containing a2ui application paths
• Monitor the upstream GitHub repository for patch commits addressing generic-binder.ts

How to Mitigate CVE-2026-92216

Immediate Actions Required

• Audit all data sources bound through the a2ui Binder component and restrict user-controllable fields that feed into openUrl
• Deploy a Content Security Policy that restricts form-action and navigation targets to trusted origins
• Add a client-side wrapper around openUrl that validates the destination scheme and host against an allowlist before navigation

Patch Information

No official patch is available at the time of publication. The maintainers have been informed through the GitHub issue tracker but have not responded. Monitor the a2ui-project repository for updates and track the VulDB advisory for coordinated disclosure information.

Workarounds

• Fork the affected component and apply a local patch that enforces URL allowlisting inside openUrl
• Route outbound navigation through a server-side redirect endpoint that validates destinations before issuing the final redirect
• Display an interstitial confirmation page for any navigation leaving the application origin

# Example allowlist enforcement wrapping openUrl (conceptual)
const ALLOWED_HOSTS = new Set(["app.example.com", "docs.example.com"]);

function safeOpenUrl(rawUrl) {
  try {
    const target = new URL(rawUrl, window.location.origin);
    if (target.protocol !== "https:" || !ALLOWED_HOSTS.has(target.host)) {
      throw new Error("Blocked untrusted redirect: " + target.href);
    }
    window.location.assign(target.href);
  } catch (err) {
    console.error(err);
  }
}