CVE-2026-23846: Tugtainer Information Disclosure Flaw

CVE-2026-23846 Overview

CVE-2026-23846 is an Information Exposure vulnerability in Tugtainer, a self-hosted application for automating updates of Docker containers. In versions prior to 1.16.1, the password authentication mechanism transmits passwords via URL query parameters instead of the HTTP request body. This insecure practice causes passwords to be logged in server access logs and potentially exposed through browser history, Referer headers, and proxy logs.

Critical Impact

Sensitive authentication credentials can be exposed through multiple logging mechanisms including server access logs, browser history, HTTP Referer headers, and proxy logs, potentially leading to unauthorized access to Docker container management systems.

Affected Products

• Tugtainer versions prior to 1.16.1

Discovery Timeline

• 2026-01-19 - CVE CVE-2026-23846 published to NVD
• 2026-01-19 - Last updated in NVD database

Technical Details for CVE-2026-23846

Vulnerability Analysis

This vulnerability falls under CWE-598 (Use of GET Request Method With Sensitive Query Strings). The core issue lies in how the Tugtainer application handles password authentication. Instead of transmitting passwords securely via the HTTP request body (POST data), the application passes credentials through URL query parameters. This design flaw violates fundamental secure coding principles for handling sensitive data.

When passwords are included in URL query parameters, they become visible and logged in multiple locations throughout the request lifecycle. Web servers typically log full URLs in access logs, browsers store URLs in history, and any intermediate proxies or load balancers may also capture and log the complete URL including the sensitive query string. Additionally, if users navigate away from the authentication page, the password may be transmitted in the HTTP Referer header to subsequent destinations.

Root Cause

The root cause of this vulnerability is an insecure implementation of the password authentication flow in the backend authentication provider. The auth_password_provider.py module extracted the password from request.query_params instead of parsing it from the JSON request body. This caused all authentication requests to include plaintext passwords in the URL structure.

Attack Vector

An attacker with access to any of the following could obtain user credentials:

• Server access logs (web server logs, application logs)
• Proxy server logs (corporate proxies, reverse proxies, CDN logs)
• Browser history on shared or compromised workstations
• Network traffic captures where URLs are visible
• Referer header leakage to external resources

The attack requires no special privileges and can be conducted passively by anyone with read access to these logging sources.

Backend Patch (Python):

         return not Config.DISABLE_AUTH and not Config.DISABLE_PASSWORD
 
     async def login(self, request: Request, response: Response):
-        password = request.query_params.get("password", "")
+        try:
+            body = await request.json()
+            password = body.get("password", "")
+        except Exception:
+            password = ""
 
         STORED_PASSWORD_HASH: str | None = self._read_password_hash()

Source: GitHub Commit 9d23bf4

Frontend Patch (TypeScript):

   onSubmitLogin(password: string): void {
     this.isLoading.set(true);
     this.authApiService
-      .login('password', {}, { password })
+      .login('password', { password }, {})
       .pipe(finalize(() => this.isLoading.set(false)))
       .subscribe({
         next: () => {

Source: GitHub Commit 9d23bf4

Detection Methods for CVE-2026-23846

Indicators of Compromise

• Web server access logs containing password= in URL query strings for Tugtainer authentication endpoints
• Proxy logs showing authentication requests with credentials visible in URLs
• Browser history entries containing password parameters in Tugtainer URLs

Detection Strategies

• Review web server access logs for patterns matching /login?password= or similar authentication endpoints with query parameters
• Implement log analysis rules to alert on sensitive parameter names appearing in URL query strings
• Audit proxy and reverse proxy logs for credential exposure in logged URLs

Monitoring Recommendations

• Configure web application firewalls (WAF) to detect and alert on credentials in URL parameters
• Enable centralized log monitoring with rules to identify password-related query strings
• Implement regular security audits of access logs to detect historical credential exposure

How to Mitigate CVE-2026-23846

Immediate Actions Required

• Upgrade Tugtainer to version 1.16.1 or later immediately
• Rotate all Tugtainer passwords that may have been exposed in logs
• Review and purge server access logs, proxy logs, and browser history that may contain exposed credentials
• Audit access to systems where logs containing passwords may have been stored

Patch Information

The vulnerability has been patched in Tugtainer version 1.16.1. The fix modifies both the backend authentication provider to read passwords from the JSON request body instead of query parameters, and the frontend to submit credentials in the request body. For detailed patch information, see the GitHub Security Advisory GHSA-f2qf-f544-xm4p.

Workarounds

• If immediate upgrade is not possible, consider placing Tugtainer behind a reverse proxy that strips or blocks requests with password parameters in URLs
• Disable password authentication temporarily if alternative authentication methods are available
• Restrict network access to the Tugtainer instance to trusted networks only until patched

# Upgrade Tugtainer to patched version
docker pull quenary/tugtainer:1.16.1
docker stop tugtainer
docker rm tugtainer
docker run -d --name tugtainer quenary/tugtainer:1.16.1