CVE-2025-42604: Meon KYC Information Disclosure Flaw

CVE-2025-42604 Overview

CVE-2025-42604 affects Meon KYC solutions where debug mode remains enabled on certain API endpoints. A remote unauthenticated attacker can query these endpoints and receive verbose error messages that disclose internal system information. The flaw maps to [CWE-1295: Debug Messages Revealing Unnecessary Information], a common misconfiguration in production deployments. CERT-In tracked this issue under advisory CIVN-2025-0082.

The disclosed information can include stack traces, framework versions, database identifiers, and internal path details. Attackers use this reconnaissance to plan follow-on attacks against the KYC workflow, its integrations, and downstream identity systems.

Critical Impact
Unauthenticated remote attackers can enumerate system internals through verbose debug responses, accelerating reconnaissance against Meon KYC deployments.

Affected Products

Meon KYC solutions with debug mode enabled on API endpoints
Deployments exposing affected endpoints to untrusted networks
Integrations relying on the affected KYC APIs for identity verification

Discovery Timeline

2025-04-23 - CVE-2025-42604 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-42604

Vulnerability Analysis

The vulnerability originates from debug mode being active on production API endpoints in Meon KYC solutions. When an API receives a malformed, unauthorized, or unexpected request, the server responds with detailed diagnostic output rather than a sanitized error. This behavior converts routine probing into an information disclosure primitive.

Detailed error responses typically expose framework versions, module names, file system paths, database query fragments, and exception traces. Each element narrows the attacker's search space for subsequent exploitation. The issue is classified under [CWE-1295], which covers debug messages that reveal unnecessary information.

Because the flaw requires no authentication and no user interaction, any network-reachable client can trigger it. Meon KYC solutions handle sensitive identity verification workflows, so leaked internals raise the risk profile of adjacent systems.

Root Cause

The root cause is a configuration defect. Debug or verbose error handling intended for development environments was retained in production API endpoints. The application returns raw exception details instead of generic error codes.

Attack Vector

An attacker sends crafted or unauthorized HTTP requests to exposed API endpoints. The endpoints respond with detailed error messages that reveal system configuration, software versions, and internal component information. No credentials or user interaction are required, and the attack originates over the network.

The vulnerability results from configuration, not code execution. See the CERT-In Vulnerability Note CIVN-2025-0082 for the vendor coordination details.

Detection Methods for CVE-2025-42604

Indicators of Compromise

Unauthenticated HTTP requests to Meon KYC API endpoints returning HTTP 4xx or 5xx responses with verbose bodies
Response payloads containing stack traces, framework identifiers, or internal file paths
Repeated probing from a single source across multiple API routes with malformed parameters

Detection Strategies

Inspect outbound API responses at the web application firewall for stack traces or debug tokens such as Traceback, Exception, or at line
Correlate error response volumes per client to detect enumeration behavior
Review API gateway logs for anomalous request patterns targeting unauthenticated endpoints

Monitoring Recommendations

Alert on API responses exceeding a defined size threshold on error status codes
Track new or unusual user agents accessing KYC API endpoints
Baseline normal error rates per endpoint and alert on statistically significant deviations

How to Mitigate CVE-2025-42604

Immediate Actions Required

Disable debug mode on all production API endpoints in Meon KYC deployments
Restrict access to affected API endpoints using network controls until the configuration is corrected
Review recent API logs for evidence of enumeration or reconnaissance activity

Patch Information

Refer to the CERT-In Vulnerability Note CIVN-2025-0082 for vendor-supplied remediation guidance. Apply the configuration updates provided by Meon and validate that debug flags are disabled across every environment.

Workarounds

Implement a reverse proxy that rewrites or strips verbose error content before responses leave the network
Configure the application server to return generic error pages for 4xx and 5xx responses
Restrict API endpoints to authenticated clients and known IP ranges where feasible

bash

# Configuration example: disable debug and enforce generic error handling
# Adjust to match the runtime used by the affected deployment
export APP_DEBUG=false
export APP_ENV=production
export LOG_LEVEL=warning
# Example generic error handler at the reverse proxy
# nginx snippet
# error_page 500 502 503 504 /50x.html;
# proxy_intercept_errors on;