Angular: SSRF and Cross-Origin Credential Disclosure via URL Resolution Discrepancy in SSR

Summary

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 in @angular/platform-server processes user-controlled resource or request URLs through HttpClient after application code validates them with WHATWG URL parsing. The resolveUrl and parseUrl utilities called String.prototype.trim(), which removed leading Unicode whitespace such as U+00A0 or U+FEFF after the input passed a same-origin check, converting a relative path into a protocol-relative attacker-controlled URL. In affected applications that attach sensitive server-side credentials such as Authorization headers to approved requests, relativeUrlsTransformerInterceptorFn then dispatched the request to the attacker-controlled origin, causing SSRF and credential disclosure. This issue is fixed in versions 20.3.30, 21.2.22, and 22.1.4.

Timeline

1. Sep 10, 2026, 6:42 PM UTCCVE published
2. Sep 15, 2026, 2:56 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: yes · Technical impact: partial

3. Sep 15, 2026, 2:56 PM UTCRecord last updated

Affected versions

• angular angular

  through 19.2.25; From 20.0.0 · fixed in 20.3.30; From 21.0.0 · fixed in 21.2.22; From 22.0.0 · fixed in 22.1.4

• @angular/platform-servernpm

  From 22.0.0 · fixed in 22.1.4

• @angular/platform-servernpm

  From 21.0.0 · fixed in 21.2.22

• @angular/platform-servernpm

  From 20.0.0 · fixed in 20.3.30

• @angular/platform-servernpm

  through 19.2.25

References 7