Executive brief
The A2UI web_core library's openUrl function fails to validate the URI scheme before passing user-supplied URLs to the browser's window.open() function. An attacker can inject a javascript: URI through a button action, causing arbitrary JavaScript to execute in the victim's browser when the button is clicked. This allows theft of session tokens, user data, and sensitive information, or performing unauthorized actions on behalf of the victim.
Technical details
The vulnerability is a cross-site scripting (XSS) flaw in the openUrl function (basic_functions.ts) which accepts agent-controlled URLs without validating the URI scheme. The Zod schema used to validate the url parameter only checks that it is a string, with no allowlist or blocklist of permitted schemes. An attacker can supply a javascript: URI as the url argument of a Button component's functionCall action. When a user clicks the button, window.open() executes the javascript: URI in the victim's browser origin, allowing arbitrary code execution. The vulnerability affects all three renderers (React, Lit, Angular) that depend on web_core's basic catalog. The issue was patched in version 0.10.2 by implementing strict scheme validation to allow only HTTP and HTTPS URIs.
Affected products
- A2UI Project web_core 0.9.0, 0.9.1, 0.9.2, 0.10.0, 0.10.1
Timeline
- 2026-08-04: disclosed: CVE-2026-10032 and GHSA-72qq-p3r5-f7wq published
- 2026-08-03: patched: Fixed in web_core version 0.10.2 via PR #1707