GHSA-45Q2-GJVG-7973

Vulnerability from github – Published: 2026-04-16 22:36 – Updated: 2026-04-16 22:36
VLAI?
Summary
Angular: SSRF via protocol-relative and backslash URLs in Angular Platform-Server
Details

Impact

A Server-Side Request Forgery (SSRF) vulnerability exists in @angular/platform-server due to improper handling of URLs during Server-Side Rendering (SSR).

When an attacker sends a request such as GET /\evil.com/ HTTP/1.1 the server engine (Express, etc.) passes the URL string to Angular’s rendering functions.

Because the URL parser normalizes the backslash to a forward slash for HTTP/HTTPS schemes, the internal state of the application is hijacked to believe the current origin is evil.com. This misinterpretation tricks the application into treating the attacker’s domain as the local origin. Consequently, any relative HttpClient requests or PlatformLocation.hostname references are redirected to the attacker controlled server, potentially exposing internal APIs or metadata services.

Affected APIs: - renderModule - renderApplication - CommonEngine (from @angular/ssr)

Non-Affected APIs: - AngularAppEngine (from @angular/ssr) - AngularNodeAppEngine (from @angular/ssr)

Attack Preconditions

  • The server has outbound network access.
  • The application uses Angular SSR via the affected APIs.
  • A pathname is passed as URL to the rendering method (e.g. using req.url).
  • The server-side code performs HTTP requests using HttpClient with relative URLs or uses PlatformLocation.hostname to build URLs.

Patches

  • 22.0.0-next.8
  • 21.2.9
  • 20.3.19
  • 19.2.21

Workarounds

Developers should implement a middleware to sanitize the request URL before it reaches Angular. This involves stripping or normalizing leading slashes:

app.use((req, res, next) => {
  // Sanitize the URL to ensure it starts with a single forward slash
  if (req.url.startsWith('//') || req.url.startsWith('/\\') || req.url.startsWith('\\')) {
     req.url = '/' + req.url.replace(/^[/\\]+/, '');
  }
  next();
});

References

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "22.0.0-next.0"
            },
            {
              "fixed": "22.0.0-next.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "21.0.0-next.0"
            },
            {
              "fixed": "21.2.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0-next.0"
            },
            {
              "fixed": "20.3.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "19.0.0-next.0"
            },
            {
              "fixed": "19.2.21"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "18.2.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T22:36:01Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact\n\nA [Server-Side Request Forgery (SSRF)](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/SSRF) vulnerability exists in `@angular/platform-server` due to improper handling of URLs during Server-Side Rendering (SSR).\n\nWhen an attacker sends a request such as `GET /\\evil.com/ HTTP/1.1` the server engine (Express, etc.) passes the URL string to Angular\u2019s rendering functions.\n\nBecause the URL parser normalizes the backslash to a forward slash for HTTP/HTTPS schemes, the internal state of the application is hijacked to believe the current origin is `evil.com`. This misinterpretation tricks the application into treating the attacker\u2019s domain as the local origin. Consequently, any relative `HttpClient` requests or `PlatformLocation.hostname` references are redirected to the attacker controlled server, potentially exposing internal APIs or metadata services.\n\n**Affected APIs:**\n- `renderModule`\n- `renderApplication`\n- `CommonEngine` (from `@angular/ssr`)\n\n**Non-Affected APIs:**\n- `AngularAppEngine` (from `@angular/ssr`)\n- `AngularNodeAppEngine` (from `@angular/ssr`)\n\n### Attack Preconditions\n- The server has outbound network access.\n- The application uses Angular SSR via the affected APIs.\n- A pathname is passed as URL to the rendering method  (e.g. using `req.url`).\n- The server-side code performs HTTP requests using `HttpClient` with relative URLs or uses `PlatformLocation.hostname` to build URLs. \n\n\n### Patches\n- 22.0.0-next.8\n- 21.2.9\n- 20.3.19\n- 19.2.21\n\n### Workarounds\nDevelopers should implement a middleware to sanitize the request URL before it reaches Angular. This involves stripping or normalizing leading slashes:\n\n```js\napp.use((req, res, next) =\u003e {\n  // Sanitize the URL to ensure it starts with a single forward slash\n  if (req.url.startsWith(\u0027//\u0027) || req.url.startsWith(\u0027/\\\\\u0027) || req.url.startsWith(\u0027\\\\\u0027)) {\n     req.url = \u0027/\u0027 + req.url.replace(/^[/\\\\]+/, \u0027\u0027);\n  }\n  next();\n});\n\n```\n### References\n- [Fix](https://github.com/angular/angular/pull/68194)",
  "id": "GHSA-45q2-gjvg-7973",
  "modified": "2026-04-16T22:36:01Z",
  "published": "2026-04-16T22:36:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/security/advisories/GHSA-45q2-gjvg-7973"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/pull/68194"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/angular/angular"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Angular: SSRF via protocol-relative and backslash URLs in Angular Platform-Server"
}


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Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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