CVE-2025-41771: Controller Web Interface SQLi Vulnerability

CVE-2025-41771 Overview

CVE-2025-41771 is an authenticated SQL injection vulnerability [CWE-89] affecting a Phoenix Contact controller's web interface. An attacker with low-privilege credentials can send crafted input to a vulnerable endpoint and manipulate queries against a SQLite database. The database in question stores only notification messages, which limits the scope of impact to the controller's notification functionality. The vulnerability is exploitable over the network without user interaction.

Critical Impact
Authenticated low-privilege attackers can inject SQL statements against the SQLite database backing the controller's notification subsystem, altering or disclosing notification data.

Affected Products

Phoenix Contact controller with affected web interface (see vendor advisory VDE-2025-056)
SQLite-backed notification component in the controller firmware
Refer to the Phoenix Contact Security Advisory for specific product and version identifiers

Discovery Timeline

2026-08-12 - CVE-2025-41771 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2025-41771

Vulnerability Analysis

The flaw is a classic SQL injection issue in an endpoint of the controller's web management interface. The endpoint requires authentication, but only low-privilege credentials are needed to reach the vulnerable code path. Input passed to the endpoint is concatenated into a SQL query executed against a SQLite database that stores notification messages.

Because the database is scoped exclusively to notifications, the attacker cannot read or modify configuration, credentials, or process control data through this flaw. The impact is confined to integrity of notification content, such as reading, altering, or deleting stored messages. The vulnerability does not directly affect controller availability or the underlying operational technology process.

Root Cause

The root cause is improper neutralization of special elements used in a SQL command [CWE-89]. User-controlled input reaching the notification endpoint is not parameterized or sufficiently sanitized before being embedded into a SQLite query. Any authenticated user with access to the vulnerable endpoint can supply payloads that alter the query's syntactic structure.

Attack Vector

Exploitation requires network access to the controller's web interface and valid credentials for a low-privilege account. The attacker submits a crafted request to the affected endpoint containing SQL metacharacters. The controller executes the manipulated query against its notification SQLite database and returns results or side effects to the attacker. No user interaction is required.

No verified public proof-of-concept code is available. See the Phoenix Contact Security Advisory for technical details.

Detection Methods for CVE-2025-41771

Indicators of Compromise

Unexpected modifications, insertions, or deletions in the controller's notification message store
Web server or application logs showing requests to notification-related endpoints containing SQL metacharacters such as single quotes, UNION, SELECT, or comment sequences (--, /*)
Authenticated sessions from low-privilege accounts issuing repeated requests to the same notification endpoint with varying payloads

Detection Strategies

Enable and centralize access logs from the controller web interface, then alert on SQL injection signatures in query strings and POST bodies
Baseline normal notification endpoint usage and flag anomalous request rates or malformed parameters from low-privilege users
Correlate authentication events with subsequent requests to the vulnerable endpoint to identify credential misuse

Monitoring Recommendations

Forward controller web and audit logs to a centralized SIEM for retention and correlation
Monitor low-privilege account activity for lateral movement toward engineering or administrative interfaces
Alert on network flows to the controller's management interface from workstations that do not normally access it

How to Mitigate CVE-2025-41771

Immediate Actions Required

Apply the vendor-provided firmware update referenced in the Phoenix Contact advisory as soon as it is available for the affected product
Restrict network access to the controller web interface to trusted engineering workstations using firewall rules or network segmentation
Enforce least privilege on controller accounts and remove unused low-privilege users
Rotate credentials on any accounts that may have been exposed on shared or internet-reachable networks

Patch Information

Refer to Phoenix Contact advisory VDE-2025-056 for fixed firmware versions and update guidance: Phoenix Contact Security Advisory. Deploy updates during a planned maintenance window and validate controller functionality after patching.

Workarounds

Place the controller behind a firewall or VPN and block direct access from untrusted networks, per ISA/IEC 62443 zone-and-conduit guidance
Disable or restrict web interface access when not required for operations
Limit notification endpoint access to administrative accounts where the controller permits per-endpoint authorization

bash

# Example: restrict controller web interface to a management subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP