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[ CVE-2026-88058 · Published 10 Sep 2026 ]

Angular SSR: XSS via Unescaped Processing Instruction (<?...?>) Nodes in Fallback Raw-Content Elements

CVSS 8.6 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 20.3.30, 21.2.22, and 22.1.4, Angular server-side rendering (SSR) in @angular/platform-server serializes ProcessingInstruction DOM nodes inside fallback raw-content elements without escaping matching ancestor closing tags. ProcessingInstruction data escaped greater-than characters but left less-than characters untouched and did not inspect fallback ancestors, so data such as a matching closing tag prematurely terminates noscript, iframe, noembed, or noframes containers. The vulnerable nodes cannot be authored through standard Angular templates; reachability requires application or library code using inject(DOCUMENT).createProcessingInstruction with attacker-controlled data or Renderer2 DOM insertion inside a fallback container. In HTML5 RAWTEXT parsing, the premature close causes subsequent sibling elements to be interpreted as live HTML and enables arbitrary JavaScript execution in a victim's browser. This issue is fixed in versions 20.3.30, 21.2.22, and 22.1.4.

[ Fixes ]Fixes and patches

  • @angular/platform-server 22.1.4Fixed version · GitHub Advisories · npm package @angular/platform-server: upgrade to 22.1.4 or later (affected >= 22.0.0, < 22.1.4)
  • @angular/platform-server 21.2.22Fixed version · GitHub Advisories · npm package @angular/platform-server: upgrade to 21.2.22 or later (affected >= 21.0.0, < 21.2.22)
  • @angular/platform-server 20.3.30Fixed version · GitHub Advisories · npm package @angular/platform-server: upgrade to 20.3.30 or later (affected >= 20.0.0, < 20.3.30)

[ Packages ]Affected open-source packages

[ References ]References