Vulnerability-Lookup

GHSA-X288-3778-4HHX

Vulnerability from github – Published: 2026-02-25 22:42 – Updated: 2026-02-25 22:42

Summary

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

Details

A Server-Side Request Forgery (SSRF) vulnerability has been identified 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 following: - Host Domain: The Host and X-Forwarded-Host headers were not checked to belong to a trusted origin. This allows an attacker to redefine the "base" of the application to an arbitrary external domain. - Path & Character Sanitization: The X-Forwarded-Host header was not checked for path segments or special characters, allowing manipulation of the base path for all resolved relative URLs. - Port Validation: The X-Forwarded-Port header was not verified as numeric, leading to malformed URI construction or injection attacks.

This vulnerability manifests in two primary ways:

Implicit Relative URL Resolution: Angular's HttpClient resolves relative URLs against this unvalidated and potentially malformed base origin. An attacker can "steer" these requests to an external server or internal service.
Explicit Manual Construction: Developers injecting the REQUEST object to manually construct URLs (for fetch or third-party SDKs) directly inherit these unsanitized values. By accessing the Host / X-Forwarded-* headers, the application logic may perform requests to attacker-controlled destinations or malformed endpoints.

Impact

When successfully exploited, this vulnerability allows for arbitrary internal request steering. This can lead to: - Credential Exfiltration: Stealing sensitive Authorization headers or session cookies by redirecting them to an attacker's server. - Internal Network Probing: Accessing and transmitting data from internal services, databases, or cloud metadata endpoints (e.g., 169.254.169.254) not exposed to the public internet. - Confidentiality Breach: Accessing sensitive information processed within the application's server-side context.

Attack Preconditions

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.
Direct Header Access: The application server is reachable by an attacker who can influence these headers without strict validation from a front-facing proxy.
Lack of Upstream Validation: The infrastructure (Cloud, CDN, or Load Balancer) does not sanitize or validate incoming headers.

Patches

21.2.0-rc.1
21.1.5
20.3.17
19.2.21

Workarounds

Use Absolute URLs: Avoid using req.headers for URL construction. Instead, use trusted variables for your base API paths.
Implement Strict Header Validation (Middleware): If you cannot upgrade immediately, implement a middleware in your server.ts to enforce numeric ports and validated hostnames.

const ALLOWED_HOSTS = new Set(['your-domain.com']);

app.use((req, res, next) => {
  const hostHeader = (req.headers['x-forwarded-host'] ?? req.headers['host'])?.toString();
  const portHeader = req.headers['x-forwarded-port']?.toString();

  if (hostHeader) {
    const hostname = hostHeader.split(':')[0];
    // Reject if hostname contains path separators or is not in allowlist
    if (/^[a-z0-9.:-]+$/i.test(hostname) || 
       (!ALLOWED_HOSTS.has(hostname) && hostname !== 'localhost')) {
      return res.status(400).send('Invalid Hostname');
    }
  }

  // Ensure port is strictly numeric if provided
  if (portHeader && !/^\d+$/.test(portHeader)) {
    return res.status(400).send('Invalid Port');
  }

  next();
});

References

Fix
Docs

Severity ?

9.2 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 21.2.0-rc.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@angular/ssr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "21.2.0-next.0"
            },
            {
              "fixed": "21.2.0-rc.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/ssr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "21.0.0-next.0"
            },
            {
              "fixed": "21.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/ssr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0-next.0"
            },
            {
              "fixed": "20.3.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/ssr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "19.2.21"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@nguniversal/common"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "16.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@nguniversal/express-engine"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "16.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27739"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-25T22:42:36Z",
    "nvd_published_at": "2026-02-25T18:23:40Z",
    "severity": "CRITICAL"
  },
  "details": "A [Server-Side Request Forgery (SSRF)](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/SSRF) vulnerability has been identified in the Angular SSR request handling pipeline. The vulnerability exists because Angular\u2019s internal URL reconstruction logic directly trusts and consumes user-controlled HTTP headers specifically the Host and `X-Forwarded-*` family to determine the application\u0027s base origin without any validation of the destination domain.\n\nSpecifically, the framework didn\u0027t have checks for the following:\n- **Host Domain**: The `Host` and `X-Forwarded-Host` headers were not checked to belong to a trusted origin. This allows an attacker to redefine the \"base\" of the application to an arbitrary external domain.\n- **Path \u0026 Character Sanitization**: The `X-Forwarded-Host` header was not checked for path segments or special characters, allowing manipulation of the base path for all resolved relative URLs.\n- **Port Validation**: The `X-Forwarded-Port` header was not verified as numeric, leading to malformed URI construction or injection attacks.\n\n\nThis vulnerability manifests in two primary ways:\n\n- **Implicit Relative URL Resolution**: Angular\u0027s `HttpClient` resolves relative URLs against this unvalidated and potentially malformed base origin. An attacker can \"steer\" these requests to an external server or internal service.\n- **Explicit Manual Construction**: Developers injecting the `REQUEST` object to manually construct URLs (for fetch or third-party SDKs) directly inherit these unsanitized values. By accessing the `Host` / `X-Forwarded-*` headers, the application logic may perform requests to attacker-controlled destinations or malformed endpoints.\n\n### Impact\n\nWhen successfully exploited, this vulnerability allows for arbitrary internal request steering. This can lead to:\n- **Credential Exfiltration**: Stealing sensitive `Authorization` headers or session cookies by redirecting them to an attacker\u0027s server.\n- **Internal Network Probing**: Accessing and transmitting data from internal services, databases, or cloud metadata endpoints (e.g., `169.254.169.254`) not exposed to the public internet.\n- Confidentiality Breach: Accessing sensitive information processed within the application\u0027s server-side context.\n\n### Attack Preconditions\n\n- The victim application must use Angular SSR (Server-Side Rendering).\n- The application must perform `HttpClient` requests using relative URLs OR manually construct URLs using the unvalidated `Host` / `X-Forwarded-*` headers using the `REQUEST` object.\n- **Direct Header Access**: The application server is reachable by an attacker who can influence these headers without strict validation from a front-facing proxy.\n- **Lack of Upstream Validation**: The infrastructure (Cloud, CDN, or Load Balancer) does not sanitize or validate incoming headers.\n\n### Patches\n\n- 21.2.0-rc.1\n- 21.1.5\n- 20.3.17\n- 19.2.21\n\n\n### Workarounds\n- **Use Absolute URLs:** Avoid using `req.headers` for URL construction. Instead, use trusted variables for your base API paths.\n- **Implement Strict Header Validation (Middleware)**: If you cannot upgrade immediately, implement a middleware in your `server.ts` to enforce numeric ports and validated hostnames.\n\n```ts\nconst ALLOWED_HOSTS = new Set([\u0027your-domain.com\u0027]);\n\napp.use((req, res, next) =\u003e {\n  const hostHeader = (req.headers[\u0027x-forwarded-host\u0027] ?? req.headers[\u0027host\u0027])?.toString();\n  const portHeader = req.headers[\u0027x-forwarded-port\u0027]?.toString();\n\n  if (hostHeader) {\n    const hostname = hostHeader.split(\u0027:\u0027)[0];\n    // Reject if hostname contains path separators or is not in allowlist\n    if (/^[a-z0-9.:-]+$/i.test(hostname) || \n       (!ALLOWED_HOSTS.has(hostname) \u0026\u0026 hostname !== \u0027localhost\u0027)) {\n      return res.status(400).send(\u0027Invalid Hostname\u0027);\n    }\n  }\n\n  // Ensure port is strictly numeric if provided\n  if (portHeader \u0026\u0026 !/^\\d+$/.test(portHeader)) {\n    return res.status(400).send(\u0027Invalid Port\u0027);\n  }\n\n  next();\n});\n```\n\n### References\n\n- [Fix](https://github.com/angular/angular-cli/pull/32516)\n- [Docs](https://angular.dev/best-practices/security#preventing-server-side-request-forgery-ssrf)",
  "id": "GHSA-x288-3778-4hhx",
  "modified": "2026-02-25T22:42:36Z",
  "published": "2026-02-25T22:42:36Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular-cli/security/advisories/GHSA-x288-3778-4hhx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27739"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular-cli/pull/32516"
    },
    {
      "type": "WEB",
      "url": "https://angular.dev/best-practices/security#preventing-server-side-request-forgery-ssrf"
    },
    {
      "type": "WEB",
      "url": "https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/SSRF"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/angular/angular-cli"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Angular SSR is vulnerable to SSRF and Header Injection via request handling pipeline"
}

CVE-2026-27739 (GCVE-0-2026-27739)

Vulnerability from cvelistv5 – Published: 2026-02-25 16:47 – Updated: 2026-02-25 16:47

Title

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

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.

Severity ?

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M

References

URL

Tags

	https://github.com/angular/angular-cli/security/a…	x_refsource_CONFIRM
	https://github.com/angular/angular-cli/pull/32516	x_refsource_MISC
	https://angular.dev/best-practices/security#preve…	x_refsource_MISC
	https://developer.mozilla.org/en-US/docs/Web/Secu…	x_refsource_MISC

Impacted products

Vendor

Product

Version

angular

angular-cli

Affected: >= 21.2.0-next.2, < 21.2.0-rc.0
Affected: >= 21.0.0-next.0, < 21.1.5
Affected: >= 20.0.0-next.0, < 20.3.17
Affected: < 19.2.21

	angular	@nguniversal/common	Affected: <= 16.2.0
	angular	@nguniversal/express-engine	Affected: <= 16.2.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "angular-cli",
          "vendor": "angular",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 21.2.0-next.2, \u003c 21.2.0-rc.0"
            },
            {
              "status": "affected",
              "version": "\u003e= 21.0.0-next.0, \u003c 21.1.5"
            },
            {
              "status": "affected",
              "version": "\u003e= 20.0.0-next.0, \u003c 20.3.17"
            },
            {
              "status": "affected",
              "version": "\u003c 19.2.21"
            }
          ]
        },
        {
          "product": "@nguniversal/common",
          "vendor": "angular",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 16.2.0"
            }
          ]
        },
        {
          "product": "@nguniversal/express-engine",
          "vendor": "angular",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 16.2.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u2019s internal URL reconstruction logic directly trusts and consumes user-controlled HTTP headers specifically the Host and `X-Forwarded-*` family to determine the application\u0027s base origin without any validation of the destination domain. Specifically, the framework didn\u0027t 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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "LOW"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-25T16:47:29.705Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/angular/angular-cli/security/advisories/GHSA-x288-3778-4hhx",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/angular/angular-cli/security/advisories/GHSA-x288-3778-4hhx"
        },
        {
          "name": "https://github.com/angular/angular-cli/pull/32516",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/angular/angular-cli/pull/32516"
        },
        {
          "name": "https://angular.dev/best-practices/security#preventing-server-side-request-forgery-ssrf",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://angular.dev/best-practices/security#preventing-server-side-request-forgery-ssrf"
        },
        {
          "name": "https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/SSRF",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/SSRF"
        }
      ],
      "source": {
        "advisory": "GHSA-x288-3778-4hhx",
        "discovery": "UNKNOWN"
      },
      "title": "Angular SSR is vulnerable to SSRF and Header Injection via request handling pipeline"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27739",
    "datePublished": "2026-02-25T16:47:29.705Z",
    "dateReserved": "2026-02-23T18:37:14.790Z",
    "dateUpdated": "2026-02-25T16:47:29.705Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-X288-3778-4HHX

Impact

Attack Preconditions

Patches

Workarounds

References

CVE-2026-27739 (GCVE-0-2026-27739)

Tags

Sightings

Nomenclature