Angular Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) Vulnerability - CVE-2026-50557

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.0-rc.2 21.2.15 20.3.22 and 19.2.22 an issue in the angular/compiler and angular/core packages allows bypassing element and attribute sanitization/validation through specific namespace workarounds. Specifically namespaced script elements (e.g. ltsvg:scriptgt or lt:svg:scriptgt) were not properly identified as script elements by the Angular template preparser allowing them to pass through template compilation without being stripped. Furthermore security context schema mappings for element attributes did not consistently handle attributes within namespaced elements (like SVG and MathML) opening up gaps where malicious namespaced attributes could bypass runtime and compile-time sanitizers. Combined these flaws enable an attacker who can inject or supply a template/tag structure with custom namespaces to bypass Angular39s script-stripping logic and attribute sanitizers leading to client-side Cross-Site Scripting (XSS). This vulnerability is fixed in 22.0.0-rc.2 21.2.15 20.3.22 and 19.2.22.