GHSA-VVXF-WJ5W-6GJ5

Vulnerability from github – Published: 2025-12-29 21:31 – Updated: 2025-12-29 21:31
VLAI
Summary
hemmelig allows SSRF Filter bypass via Secret Request functionality
Details

Summary

A Server-Side Request Forgery (SSRF) filter bypass vulnerability exists in the webhook URL validation of the Secret Requests feature. The application attempts to block internal/private IP addresses but can be bypassed using DNS rebinding (e.g., localtest.me which resolves to 127.0.0.1) or open redirect services (e.g., httpbin.org/redirect-to). This allows an authenticated user to make the server initiate HTTP requests to internal network resources.

Details

The vulnerability exists in the isPublicUrl function located in /api/lib/utils.ts. The function validates webhook URLs against a blocklist of private IP patterns:

export const isPublicUrl = (url: string): boolean => {
    const parsed = new URL(url);
    const hostname = parsed.hostname.toLowerCase();

    const blockedPatterns = [
        /^localhost$/,
        /^127\.\d{1,3}\.\d{1,3}\.\d{1,3}$/,
        /^192\.168\.\d{1,3}\.\d{1,3}$/,
        // ... other patterns
    ];

    return !blockedPatterns.some((pattern) => pattern.test(hostname));
};

The validation is flawed because:

  1. DNS Rebinding Bypass: It only checks the hostname string, not the resolved IP address. Domains like localtest.me pass validation (not matching any blocked pattern) but resolve to 127.0.0.1.

  2. Open Redirect Bypass: External URLs like httpbin.org/redirect-to?url=http://127.0.0.1 pass validation since httpbin.org is a public domain. When the server follows the redirect, it connects to the internal address.

PoC

Optional: On the container that runs Hemmelig application, host a temporary port with the following command: 

node -e "require('http').createServer((req,res)=>{console.log(req.method,req.url,req.headers);res.end('ok')}).listen(8080,()=>console.log('Listening on 8080'))"
  1. Log in as an user
  2. Switch to Secret Requests tab and create a new request
  3. When inside the request dialog, there are 2 possible payloads that can be used on the Webhook URL input to bypass SSRF
1. Using domain redirect: http://localtest.me:PORT
2. Using httpbin to perform a redirect: httpbin.org/redirect-to?url=http://127.0.0.1:PORT
  1. Open a new browser/tab and confirm the request by creating a secret. Upon clicking save, the port we hosted we receive a request. image

Otherwise, if the port doesn't exist, a similar error in the logs can be found:

Secret request webhook delivery failed after retries: TypeError: fetch failed
    at node:internal/deps/undici/undici:15845:13
    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)
    at async sendSecretRequestWebhook (/app/api/routes/secret-requests.ts:58:34) {
  [cause]: Error: connect ECONNREFUSED 127.0.0.1:80
      at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1637:16) {
    errno: -111,
    code: 'ECONNREFUSED',
    syscall: 'connect',
    address: '127.0.0.1',
    port: 80
  }
}

Impact

While the SSRF filter can be bypassed, the practical impact is limited because this is a Blind SSRF, there is no response reflected. But with certain technique like response-timing, the attackers can still indicate whether or not a port is opened.

Remediation

Replace hostname-based validation with IP resolution checking:

import { isIP } from 'is-ip';
import dns from 'dns/promises';

export const isPublicUrl = async (url: string): Promise<boolean> => {
    const parsed = new URL(url);
    const hostname = parsed.hostname;

    // Resolve hostname to IP
    let addresses: string[];
    try {
        if (isIP(hostname)) {
            addresses = [hostname];
        } else {
            addresses = await dns.resolve4(hostname).catch(() => []);
            const ipv6 = await dns.resolve6(hostname).catch(() => []);
            addresses = [...addresses, ...ipv6];
        }
    } catch {
        return false;
    }

    // Check resolved IPs against blocklist
    const privateRanges = [
        /^127\./,
        /^10\./,
        /^192\.168\./,
        /^172\.(1[6-9]|2\d|3[0-1])\./,
        /^169\.254\./,
        /^::1$/,
        /^fe80:/i,
        /^fc00:/i,
        /^fd/i,
    ];

    return addresses.length > 0 && !addresses.some(ip => 
        privateRanges.some(pattern => pattern.test(ip))
    );
};

Additionally, disable following redirects in the webhook fetch call or re-validate the URL after each redirect.

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

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hemmelig"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.3.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-69206"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-29T21:31:04Z",
    "nvd_published_at": "2025-12-29T16:15:44Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nA Server-Side Request Forgery (SSRF) filter bypass vulnerability exists in the webhook URL validation of the Secret Requests feature. The application attempts to block internal/private IP addresses but can be bypassed using DNS rebinding (e.g., `localtest.me` which resolves to `127.0.0.1`) or open redirect services (e.g., `httpbin.org/redirect-to`). This allows an authenticated user to make the server initiate HTTP requests to internal network resources.\n\n### Details\nThe vulnerability exists in the `isPublicUrl` function located in `/api/lib/utils.ts`. The function validates webhook URLs against a blocklist of private IP patterns:\n\n```typescript\nexport const isPublicUrl = (url: string): boolean =\u003e {\n    const parsed = new URL(url);\n    const hostname = parsed.hostname.toLowerCase();\n    \n    const blockedPatterns = [\n        /^localhost$/,\n        /^127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}$/,\n        /^192\\.168\\.\\d{1,3}\\.\\d{1,3}$/,\n        // ... other patterns\n    ];\n    \n    return !blockedPatterns.some((pattern) =\u003e pattern.test(hostname));\n};\n```\n\n**The validation is flawed because:**\n\n1. **DNS Rebinding Bypass**: It only checks the hostname string, not the resolved IP address. Domains like `localtest.me` pass validation (not matching any blocked pattern) but resolve to `127.0.0.1`.\n\n2. **Open Redirect Bypass**: External URLs like `httpbin.org/redirect-to?url=http://127.0.0.1` pass validation since `httpbin.org` is a public domain. When the server follows the redirect, it connects to the internal address.\n\n### PoC\nOptional: On the container that runs Hemmelig application, host a temporary port with the following command: \n```\nnode -e \"require(\u0027http\u0027).createServer((req,res)=\u003e{console.log(req.method,req.url,req.headers);res.end(\u0027ok\u0027)}).listen(8080,()=\u003econsole.log(\u0027Listening on 8080\u0027))\"\n```\n1. Log in as an user\n2. Switch to `Secret Requests` tab and create a new request\n3. When inside the request dialog, there are 2 possible payloads that can be used on the `Webhook URL` input to bypass SSRF\n```\n1. Using domain redirect: http://localtest.me:PORT\n2. Using httpbin to perform a redirect: httpbin.org/redirect-to?url=http://127.0.0.1:PORT\n```\n4. Open a new browser/tab and confirm the request by creating a secret. Upon clicking save, the port we hosted we receive a request. \n\u003cimg width=\"795\" height=\"310\" alt=\"image\" src=\"https://github.com/user-attachments/assets/95d559e5-ead2-4b5d-8e53-9ddec3416953\" /\u003e\n\nOtherwise, if the port doesn\u0027t exist, a similar error in the logs can be found:\n```\nSecret request webhook delivery failed after retries: TypeError: fetch failed\n    at node:internal/deps/undici/undici:15845:13\n    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)\n    at async sendSecretRequestWebhook (/app/api/routes/secret-requests.ts:58:34) {\n  [cause]: Error: connect ECONNREFUSED 127.0.0.1:80\n      at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1637:16) {\n    errno: -111,\n    code: \u0027ECONNREFUSED\u0027,\n    syscall: \u0027connect\u0027,\n    address: \u0027127.0.0.1\u0027,\n    port: 80\n  }\n}\n```\n### Impact\nWhile the SSRF filter can be bypassed, the practical impact is limited because this is a Blind SSRF, there is no response reflected. But with certain technique like response-timing, the attackers can still indicate whether or not a port is opened.\n\n### Remediation\nReplace hostname-based validation with IP resolution checking:\n```typescript\nimport { isIP } from \u0027is-ip\u0027;\nimport dns from \u0027dns/promises\u0027;\n\nexport const isPublicUrl = async (url: string): Promise\u003cboolean\u003e =\u003e {\n    const parsed = new URL(url);\n    const hostname = parsed.hostname;\n    \n    // Resolve hostname to IP\n    let addresses: string[];\n    try {\n        if (isIP(hostname)) {\n            addresses = [hostname];\n        } else {\n            addresses = await dns.resolve4(hostname).catch(() =\u003e []);\n            const ipv6 = await dns.resolve6(hostname).catch(() =\u003e []);\n            addresses = [...addresses, ...ipv6];\n        }\n    } catch {\n        return false;\n    }\n    \n    // Check resolved IPs against blocklist\n    const privateRanges = [\n        /^127\\./,\n        /^10\\./,\n        /^192\\.168\\./,\n        /^172\\.(1[6-9]|2\\d|3[0-1])\\./,\n        /^169\\.254\\./,\n        /^::1$/,\n        /^fe80:/i,\n        /^fc00:/i,\n        /^fd/i,\n    ];\n    \n    return addresses.length \u003e 0 \u0026\u0026 !addresses.some(ip =\u003e \n        privateRanges.some(pattern =\u003e pattern.test(ip))\n    );\n};\n```\nAdditionally, disable following redirects in the webhook fetch call or re-validate the URL after each redirect.",
  "id": "GHSA-vvxf-wj5w-6gj5",
  "modified": "2025-12-29T21:31:04Z",
  "published": "2025-12-29T21:31:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/HemmeligOrg/Hemmelig.app/security/advisories/GHSA-vvxf-wj5w-6gj5"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-69206"
    },
    {
      "type": "WEB",
      "url": "https://github.com/HemmeligOrg/Hemmelig.app/commit/6c909e571d0797ee3bbd2c72e4eb767b57378228"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/HemmeligOrg/Hemmelig.app"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "hemmelig allows SSRF Filter bypass via Secret Request functionality"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.