Angular Client Hydration DOM Clobbering & Response-Cache Poisoning

Summary

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, to optimize client-side bootstrap in Server-Side Rendered (SSR) environments, Angular supports Hydration via provideClientHydration(). During SSR, Angular serializes the application's runtime state (such as cached HttpClient responses) and outputs it into the HTML stream as a <script> tag with a predictable identifier. During client bootstrap, Angular recovers this state by looking up the element via document.getElementById('ng-state') and parsing its text content. Because the DOM element lookup for the state container is predictable and relies solely on the ID selector (ng-state), it is susceptible to DOM Clobbering. If the application binds untrusted user input or CMS content to element properties such as id (e.g., <div [id]="userInput"> or <a id="ng-state">) before the genuine <script> tag is parsed by the browser, the attacker-controlled element takes precedence in the DOM lookup. During hydration, when Angular calls document.getElementById('ng-state'), the browser returns the attacker's clobbered element. Angular then attempts to parse the text content or attributes of this clobbered element as JSON. This vulnerability is fixed in 22.0.1, 21.2.17, and 20.3.25.

Timeline

1. Jun 22, 2026, 3:30 PM UTCCVE published
2. Jun 22, 2026, 4:00 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Jun 22, 2026, 4:00 PM UTCRecord last updated

Affected versions

• angular angular

  through 19.2.25

• @angular/corenpm

  From 22.0.0-next.0 · fixed in 22.0.1

• @angular/corenpm

  From 21.0.0-next.0 · fixed in 21.2.17

• @angular/corenpm

  From 20.0.0-next.0 · fixed in 20.3.25

• @angular/corenpm

  through 19.2.25

References 3