Description

A vulnerability was detected in NginxProxyManager nginx-proxy-manager up to 2.15.1. This impacts the function internalCertificate.validate of the file backend/internal/certificate.js of the component Validate Route. The manipulation results in missing authentication. The attack can be launched remotely. The exploit is now public and may be used. Endpoint only processes and echoes back the certificate the caller submits (no stored data leaked); the real risk is unauthenticated openssl processing of attacker input. The project was informed of the problem early through an issue report but has not responded yet.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.3",
  "pubDate": "2026-09-20T06:16:50.477Z",
  "pubdate": "2026-09-20T06:16:50.477Z",
  "executiveSummary": "A critical security vulnerability exists within NginxProxyManager up to version 2.15.1, specifically affecting the internal certificate validation route.\nThe vulnerability is characterized as an authentication bypass, allowing remote, unauthenticated attackers to interact with the backend OpenSSL processing functionality.\nThe flaw resides in the internalCertificate.validate function located in backend/internal/certificate.js. By failing to enforce proper authentication checks, the endpoint allows arbitrary input to be processed by the underlying OpenSSL engine.\nWhile the vulnerability does not result in the leakage of stored data, it exposes the system to potential exploitation of the OpenSSL library through crafted payloads.\nThe risk is significant due to the remote exploitability and the potential for memory corruption or other OpenSSL-related vulnerabilities triggered via malicious certificate structures.\nSince the project maintainers have not yet provided a patch, the system remains vulnerable to any remote actor capable of reaching the management interface.",
  "technicalDetails": "The vulnerability exists within the Validate Route component of NginxProxyManager, specifically targeting the internalCertificate.validate function within the backend/internal/certificate.js file.\nThe root cause of this vulnerability is a missing authentication check that fails to verify the identity of the user before allowing the application to invoke backend processing functions.\nThe application architecture exposes an endpoint designed to validate SSL/TLS certificates provided by the user. When a request is submitted, the application passes the provided certificate data directly to the underlying OpenSSL libraries for parsing and validation.\nBecause the function lacks an access control layer, an unauthenticated remote attacker can send a crafted HTTP request containing a malicious certificate payload to this endpoint.\nThe application then proceeds to echo back the certificate data or perform validation operations using OpenSSL, effectively acting as an unauthenticated interface to the server's cryptographic stack.\nThe attack flow proceeds as follows: 1) The attacker identifies the exposed internalCertificate.validate endpoint. 2) The attacker generates a malicious or malformed X.509 certificate designed to trigger vulnerabilities in the OpenSSL parser. 3) The attacker submits this payload to the NginxProxyManager instance via a standard HTTP request. 4) The application, without checking for an active session or administrative privileges, hands the malicious input to the OpenSSL engine.\nThe impact of this behavior is primarily centered on the potential exploitation of the OpenSSL library. By forcing the application to process arbitrary inputs, an attacker may be able to trigger memory management errors, buffer overflows, or other vulnerabilities inherent in the parsing of complex certificate structures.\nWhile the current scope indicates that no internal data is directly leaked during this process, the ability to interact with the OpenSSL library without authentication constitutes a severe security regression. The remote nature of this flaw makes it highly accessible to attackers scanning for unpatched services."
}