CVE-2026-22910: Authentication Bypass Vulnerability

CVE-2026-22910 Overview

CVE-2026-22910 is a hardcoded credentials vulnerability affecting industrial devices manufactured by SICK AG. The affected device is deployed with weak and publicly known default passwords for certain hidden user levels, significantly increasing the risk of unauthorized access. This vulnerability falls under CWE-1391 (Use of Weak Credentials), which describes scenarios where authentication mechanisms rely on credentials that can be easily guessed, discovered, or bypassed.

Critical Impact

Attackers with network access can leverage well-known default credentials to gain unauthorized access to hidden administrative user levels, potentially compromising industrial control system integrity and exposing sensitive operational data.

Affected Products

• SICK AG industrial devices (specific models detailed in vendor advisory)
• Devices with hidden user levels using default credentials
• Industrial control system components with network connectivity

Discovery Timeline

• 2026-01-15 - CVE-2026-22910 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2026-22910

Vulnerability Analysis

This vulnerability stems from the presence of hidden user accounts with weak, publicly known default passwords embedded in the device firmware. These hidden user levels are often used for factory diagnostics, maintenance, or debugging purposes but are inadvertently left accessible in production deployments. The vulnerability allows remote attackers to authenticate to these hidden accounts without requiring any prior privileges or user interaction.

The network-accessible nature of this vulnerability means that any attacker who can reach the device over the network can attempt authentication using known default credentials. Since these credentials are publicly documented or easily discoverable through firmware analysis, the barrier to exploitation is extremely low. Successful exploitation grants attackers access to privileged functionality that is typically restricted from normal users.

Root Cause

The root cause of this vulnerability is the use of weak credentials (CWE-1391) in the form of hardcoded default passwords for hidden user levels. During the device development and manufacturing process, these accounts were created for legitimate purposes such as factory testing or field service operations. However, the credentials were not uniquely generated per device, nor were they required to be changed during initial deployment. The combination of:

1. Static, weak default passwords across all devices of the same model
2. Hidden user accounts not visible in standard administrative interfaces
3. Network accessibility without additional authentication barriers

creates an easily exploitable attack surface that persists across the entire installed base of affected devices.

Attack Vector

The attack vector for CVE-2026-22910 is network-based, requiring no authentication, user interaction, or special privileges. An attacker with network connectivity to the vulnerable device can attempt to authenticate using publicly known or easily guessed default credentials for hidden user levels.

The exploitation process typically involves:

1. Network reconnaissance to identify SICK industrial devices
2. Identification of authentication interfaces (web, telnet, SSH, or proprietary protocols)
3. Attempting authentication with documented default credentials
4. Accessing privileged functionality upon successful authentication

Since no code examples are available from verified sources, organizations should consult the SICK CSAF Security Advisory for specific technical details regarding affected services and default credential combinations.

Detection Methods for CVE-2026-22910

Indicators of Compromise

• Successful authentication events from unexpected or external IP addresses to hidden user accounts
• Unusual access patterns to diagnostic or maintenance interfaces outside normal business hours
• Configuration changes or command execution logged under hidden user account activity
• Network traffic to administrative ports from unauthorized network segments

Detection Strategies

• Implement network traffic analysis to identify authentication attempts against industrial devices from unauthorized sources
• Deploy honeypot accounts or canary tokens that alert on any authentication attempt
• Monitor device logs for successful logins to accounts not associated with normal operational use
• Utilize industrial intrusion detection systems (IDS) configured with rules for default credential usage patterns

Monitoring Recommendations

• Enable comprehensive logging on all SICK industrial devices and forward logs to a centralized SIEM
• Establish baseline authentication patterns and alert on deviations
• Implement network segmentation monitoring to detect unauthorized access attempts to OT networks
• Review device access logs regularly as part of operational security procedures

How to Mitigate CVE-2026-22910

Immediate Actions Required

• Change all default passwords on affected devices immediately, including hidden user accounts if accessible
• Implement network segmentation to isolate industrial devices from general corporate networks and the internet
• Disable or restrict access to hidden user accounts where possible through device configuration
• Apply firewall rules to limit network access to affected devices to only authorized management stations

Patch Information

SICK AG has published security information and guidance regarding this vulnerability. Organizations should review the official security advisories and apply any available firmware updates:

• SICK PSIRT Updates - Official security response team updates
• SICK Security Advisory SCA-2026-0001 (PDF) - Detailed vulnerability information
• SICK Cybersecurity Operating Guidelines - General security hardening guidance

Organizations should also follow CISA ICS Recommended Practices for securing industrial control systems.

Workarounds

• Place affected devices behind a firewall and restrict network access to authorized personnel only
• Implement VPN or jump server requirements for remote access to industrial networks
• Deploy network monitoring solutions to detect and alert on authentication anomalies
• Consider physical access controls to prevent local exploitation if network isolation is not feasible

# Network segmentation example - restrict access to industrial device subnet
# Firewall rule to allow only authorized management station (192.168.100.10) to access device
iptables -A INPUT -s 192.168.100.10 -d 10.0.50.0/24 -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -s 192.168.100.10 -d 10.0.50.0/24 -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -d 10.0.50.0/24 -j DROP