Bug 2491459 (CVE-2026-50556)

Summary: CVE-2026-50556 @angular/platform-server: domino: Angular Platform Server: Cross-Site Scripting via unescaped `</noscript>` tags in dynamic content
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: gmalinko, janstey, pdelbell, rhel-process-autobot, rstepani, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in @angular/platform-server. This Cross-Site Scripting (XSS) vulnerability exists in its DOM emulation dependency, domino, when handling the content of `<noscript>` elements during server-side rendering. A remote attacker could exploit this by injecting unescaped closing `</noscript>` tags within dynamic text content. This allows for the execution of arbitrary code in the user's browser context, potentially leading to information disclosure or other malicious activities.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-06-22 18:02:40 UTC
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, 21.2.16, 20.3.24, and 19.2.25, a Cross-Site Scripting (XSS) vulnerability exists in @angular/platform-server's DOM emulation dependency (domino) when serializing the content of <noscript> elements. When rendering dynamic text content inside a <noscript> element via template bindings (such as {{ value }} or [textContent]), the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), domino is configured with scripting enabled, meaning <noscript> is treated as a raw-text element. However, domino's serializer completely omitted <noscript> from the list of raw-text elements requiring closing-tag escaping during DOM serialization. As a result, any occurrence of </noscript> in the bound dynamic text was never escaped under any circumstances. The unescaped closing tag was serialized directly into the output HTML (e.g. <noscript></noscript><script>alert(1)</script></noscript>). When parsed by a browser, it closes the <noscript> block early, allowing the injected <script> block to execute in the user's browser context, causing same-origin Cross-Site Scripting (XSS). This vulnerability is fixed in 22.0.0-rc.2, 21.2.16, 20.3.24, and 19.2.25.