Angular: Two-Way Property Binding Sanitization Bypass (XSS)

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.1, 21.2.17, and 20.3.25, an issue in the @angular/compiler package allows bypassing DOM property sanitization through the use of two-way property bindings. Specifically, when a native DOM property that requires sanitization (such as innerHTML, srcdoc, src, href, data, or sandbox) is bound using the two-way binding syntax (e.g., [(innerHTML)]="value" or bindon-innerHTML="value"), the Angular template compiler failed to apply the appropriate schema-derived sanitizer resolution to the TwoWayProperty operation. As a result, native two-way DOM bindings were emitted without the required sanitizer function, whereas equivalent one-way bindings would be properly sanitized. This flaw enables an attacker who can control the value of a two-way bound sensitive property to bypass Angular's built-in sanitization logic, potentially leading to client-side Cross-Site Scripting (XSS). This vulnerability is fixed in 22.0.1, 21.2.17, and 20.3.25.