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TI-2026-22099 Aliases CVE-2026-27739GHSA-x288-3778-4hhx

Angular SSR is vulnerable to SSRF and Header Injection via request handling pipeline

Priority MEDIUM 46CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

The Angular SSR is a server-rise rendering tool for Angular applications. Versions prior to 21.2.0-rc.1, 21.1.5, 20.3.17, and 19.2.21 have a Server-Side Request Forgery (SSRF) vulnerability in the Angular SSR request handling pipeline. The vulnerability exists because Angular’s internal URL reconstruction logic directly trusts and consumes user-controlled HTTP headers specifically the Host and `X-Forwarded-*` family to determine the application's base origin without any validation of the destination domain. Specifically, the framework didn't have checks for the host domain, path and character sanitization, and port validation. This vulnerability manifests in two primary ways: implicit relative URL resolution and explicit manual construction. When successfully exploited, this vulnerability allows for arbitrary internal request steering. This can lead to credential exfiltration, internal network probing, and a confidentiality breach. In order to be vulnerable, the victim application must use Angular SSR (Server-Side Rendering), the application must perform `HttpClient` requests using relative URLs OR manually construct URLs using the unvalidated `Host` / `X-Forwarded-*` headers using the `REQUEST` object, the application server must be reachable by an attacker who can influence these headers without strict validation from a front-facing proxy, and the infrastructure (Cloud, CDN, or Load Balancer) must not sanitize or validate incoming headers. Versions 21.2.0-rc.1, 21.1.5, 20.3.17, and 19.2.21 contain a patch. Some workarounds are available. Avoid using `req.headers` for URL construction. Instead, use trusted variables for base API paths. Those who cannot upgrade immediately should implement a middleware in their `server.ts` to enforce numeric ports and validated hostnames.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00553 46th percentileScored 2026-11-07
Fix Fixed angular-cli (angular): 21.2.0-rc.0, 21.1.5, 20.3.17 +1@angular/ssr (npm): 21.2.0-rc.1, 21.1.5, 20.3.17 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
angularangular-cli21.2.0-next.2 to before 21.2.0-rc.0; 21.0.0-next.0 to before 21.1.5; 20.0.0-next.0 to before 20.3.17; before 19.2.2121.2.0-rc.0, 21.1.5, 20.3.17, 19.2.21Patch availableCNA
angular@nguniversal/commonup to 16.2.0—No fix listedCNA
angular@nguniversal/express-engineup to 16.2.0—No fix listedCNA
—@angular/ssr (npm)21.2.0-next.0 to before 21.2.0-rc.121.2.0-rc.1Patch availableGHSA-x288-3778-4hhx
—@angular/ssr (npm)21.0.0-next.0 to before 21.1.521.1.5Patch availableGHSA-x288-3778-4hhx
—@angular/ssr (npm)20.0.0-next.0 to before 20.3.1720.3.17Patch availableGHSA-x288-3778-4hhx
—@angular/ssr (npm)before 19.2.2119.2.21Patch availableGHSA-x288-3778-4hhx
—@nguniversal/common (npm)up to 16.2.0—No fix listedGHSA-x288-3778-4hhx
—@nguniversal/express-engine (npm)up to 16.2.0—No fix listedGHSA-x288-3778-4hhx
  • angular-cli Vendorangular Affected 21.2.0-next.2 to before 21.2.0-rc.0; 21.0.0-next.0 to before 21.1.5; 20.0.0-next.0 to before 20.3.17; before 19.2.21 Fixed in 21.2.0-rc.0, 21.1.5, 20.3.17, 19.2.21 Patch available CNA
  • @nguniversal/common Vendorangular Affected up to 16.2.0 Fixed in — No fix listed CNA
  • @nguniversal/express-engine Vendorangular Affected up to 16.2.0 Fixed in — No fix listed CNA
  • @angular/ssr (npm) Vendor— Affected 21.2.0-next.0 to before 21.2.0-rc.1 Fixed in 21.2.0-rc.1 Patch available GHSA-x288-3778-4hhx
  • @angular/ssr (npm) Vendor— Affected 21.0.0-next.0 to before 21.1.5 Fixed in 21.1.5 Patch available GHSA-x288-3778-4hhx
  • @angular/ssr (npm) Vendor— Affected 20.0.0-next.0 to before 20.3.17 Fixed in 20.3.17 Patch available GHSA-x288-3778-4hhx
  • @angular/ssr (npm) Vendor— Affected before 19.2.21 Fixed in 19.2.21 Patch available GHSA-x288-3778-4hhx
  • @nguniversal/common (npm) Vendor— Affected up to 16.2.0 Fixed in — No fix listed GHSA-x288-3778-4hhx
  • @nguniversal/express-engine (npm) Vendor— Affected up to 16.2.0 Fixed in — No fix listed GHSA-x288-3778-4hhx

Remediation

  • Fix · CNA angular-cli (angular) Fixed in 21.2.0-rc.0, 21.1.5, 20.3.17, 19.2.21
  • Fix · GHSA-x288-3778-4hhx @angular/ssr (npm) Fixed in 21.2.0-rc.1 Advisory →
  • Fix · GHSA-x288-3778-4hhx @angular/ssr (npm) Fixed in 21.1.5 Advisory →
  • Fix · GHSA-x288-3778-4hhx @angular/ssr (npm) Fixed in 20.3.17 Advisory →
  • Fix · GHSA-x288-3778-4hhx @angular/ssr (npm) Fixed in 19.2.21 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-27739
  2. 2026-10-03 Alias added: GHSA-x288-3778-4hhx

References

Advisory 1

Other 5

  • TI-2026-74069 Infinite loop in Angular SSR HTML parser allows denial of service CVSS 4.0HIGH 8.7
  • TI-2026-60076 Angular: SSRF and Cross-Origin Credential Disclosure via URL Resolution Discrepancy in SSR CVSS 4.0HIGH 8.6
  • TI-2026-60080 Angular: SSR XSS via Unescaped <template> Content Across DocumentFragment Boundaries in Fallback Raw-Content Elements CVSS 4.0HIGH 8.6
  • TI-2026-60078 Angular: SSR XSS via Unescaped Processing Instruction (<?...?>) Nodes in Fallback Raw-Content Elements CVSS 4.0HIGH 8.6
  • TI-2025-38694 Server-Side Request Forgery (SSRF) in Angular SSR CVSS 4.0HIGH 8.7
  • TI-2026-22098 Angular SSR has an Open Redirect via X-Forwarded-Prefix CVSS 4.0MEDIUM 6.9
See all 46 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences