CVE-2025-30037: Authentication Bypass Vulnerability

CVE-2025-30037 Overview

CVE-2025-30037 describes a missing authentication flaw [CWE-306] where an application exposes internal endpoints to unauthenticated network clients. The affected system serves several routes containing /int/ in their path on port 443/tcp. These endpoints are intended for internal service-to-service communication but accept requests from any host able to reach the application server. Attackers on an adjacent network can interact with sensitive internal functionality without supplying credentials. CERT Polska published an advisory describing the issue under their disclosure process.

Critical Impact
Unauthenticated adjacent attackers can invoke internal-only endpoints, exposing high-confidentiality and high-integrity data within the affected application and downstream systems.

Affected Products

Affected vendor and product details are not disclosed in the public CVE record
Refer to the CERT Polska Security Advisory for coordinated disclosure context
Any deployment exposing /int/ routes on port 443/tcp should be reviewed

Discovery Timeline

2025-08-27 - CVE-2025-30037 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-30037

Vulnerability Analysis

The vulnerability is a missing authentication for critical function weakness [CWE-306]. The application server publishes routes under paths containing /int/ that the developers intended to restrict to internal services. The deployed configuration does not enforce network-level isolation or application-layer authentication on those routes. Any client able to reach the server on port 443/tcp can invoke them directly.

The CVSS vector indicates an adjacent-network attack vector with no privileges and no user interaction required. The impact covers both confidentiality and integrity at the vulnerable component and at subsequent systems. This pattern is common when applications rely on perimeter assumptions rather than enforcing authentication on every endpoint.

Root Cause

The root cause is a failure to apply authentication and authorization controls to endpoints assumed to be reachable only from a trusted internal network. The /int/ URL convention served as informal segmentation rather than an enforced security boundary. No ingress filtering, mutual TLS, or token validation gates the routes.

Attack Vector

An attacker on the adjacent network sends standard HTTPS requests to the exposed /int/ endpoints. Because no authentication is required, the server processes the requests as if they originated from a trusted internal caller. Successful interaction can read internal data, modify resources, or pivot to downstream systems referenced by the internal API.

No verified exploit code is published for this CVE. Consult the CERT Polska Security Advisory for additional technical context.

Detection Methods for CVE-2025-30037

Indicators of Compromise

Unexpected HTTPS requests to URI paths containing /int/ originating from non-internal source addresses
Successful HTTP 200 responses on internal endpoints from clients outside the expected service mesh
Spikes in request volume to internal routes during off-hours or from new user agents

Detection Strategies

Enable verbose access logging on the application server and flag any request to paths matching /int/* that does not originate from an allow-listed internal address
Deploy a web application firewall rule that blocks or alerts on external traffic to /int/ URI patterns
Review network flow records for sessions to port 443/tcp on the application server from segments that should not have access

Monitoring Recommendations

Centralize application and proxy logs into a SIEM and build correlations on source IP, requested path, and response status
Monitor for authentication-free responses on routes that should require credentials
Alert on configuration drift in reverse proxy or ingress rules that govern internal route exposure

How to Mitigate CVE-2025-30037

Immediate Actions Required

Restrict network access to /int/ endpoints using firewall rules, ingress policies, or a reverse proxy access control list
Require authentication, such as mutual TLS or signed service tokens, on every internal route before re-enabling external reachability
Audit application logs for prior unauthenticated access to /int/ routes and treat confirmed access as a potential data exposure incident

Patch Information

No vendor patch identifier is listed in the public CVE record. Follow guidance in the CERT Polska Security Advisory and apply vendor updates when available.

Workarounds

Block external traffic to URI paths containing /int/ at the load balancer or reverse proxy until authentication is enforced in the application
Place the application server behind a private network segment and expose only the public-facing routes through an authenticated gateway
Implement network segmentation so port 443/tcp on the application server is reachable only from authorized internal service subnets

bash

# Example NGINX configuration blocking external access to internal routes
location ~* ^/int/ {
    allow 10.0.0.0/8;
    deny all;
    proxy_pass http://upstream_app;
}