CVE-2026-88056: Angular: SSRF and Cross-Origin Credential Disclosure via URL Resolution Discrepancy in SSR

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-09-10 · updated 2026-09-29
Weakness: CWE-918

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 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.

Affected products

angular: from 19.0.0 through 19.2.25; from 20.0.0 before 20.3.30; from 21.0.0 before 21.2.22; from 22.0.0 before 22.1.4 — fixed in 20.3.30, 21.2.22, 22.1.4

How to fix

Upgrade to a fixed version: angular 20.3.30, 21.2.22, 22.1.4. Check the vendor advisory for mitigations.

References

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