Executive brief
A vulnerability in the Angular web development framework's server-side rendering component could allow attackers to redirect internal server requests to malicious external servers. This occurs when the server incorrectly processes specially formatted web addresses, bypassing security filters intended to restrict communication to trusted domains. If exploited, sensitive information like session cookies or internal authorization tokens could be sent to an attacker, and the attacker could potentially inject malicious content into the website seen by other users.
Technical details
A Server-Side Request Forgery (SSRF) vulnerability exists in @angular/platform-server due to a parser differential between the strict WHATWG URL parser (used for allowlist validation) and the lenient Domino URL parser (used for DOM emulation). When an attacker provides a malformed URL with a double port structure (e.g., 'evil.com:80:80'), Node's strict parser fails validation and skips host checks, while the lenient parser accepts it and resolves the origin to the attacker's domain. The 'relativeUrlsTransformerInterceptorFn' then resolves relative backend API calls against this malicious origin. This allows attackers to intercept outgoing requests containing sensitive credentials or perform response injection. The issue is fixed in versions 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23.
Affected products
- Google Angular < 19.2.23, >= 19.0.0-next.0 < 19.2.23, >= 20.0.0-next.0 < 20.3.22, >= 21.0.0-next.0 < 21.2.15, >= 22.0.0-next.0 < 22.0.0-rc.2
Timeline
- 2026-05-26: other: Fix PR submitted to GitHub
- 2026-05-28: advisory: GitHub Security Advisory published
- 2026-06-22: disclosed: NVD publication date