CVE-2025-54816: WebSocket Auth Bypass Vulnerability

CVE-2025-54816 Overview

CVE-2025-54816 is a critical authentication bypass vulnerability affecting WebSocket endpoints that fail to enforce proper authentication mechanisms. This vulnerability allows unauthorized users to establish WebSocket connections without valid credentials, enabling attackers to gain unauthorized access to sensitive data or perform unauthorized actions on affected systems. The lack of authentication requirements creates a direct path for privilege escalation and potentially compromises the security of the entire system.

Critical Impact

Unauthenticated attackers can establish WebSocket connections to exploit this weakness, leading to unauthorized data access, privilege escalation, and potential full system compromise.

Affected Products

• Industrial Control Systems (ICS) components (refer to CISA ICS Advisory ICSA-26-022-08 for specific product details)
• OT (Operational Technology) systems with vulnerable WebSocket implementations

Discovery Timeline

• 2026-01-22 - CVE-2025-54816 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2025-54816

Vulnerability Analysis

This vulnerability is classified under CWE-306 (Missing Authentication for Critical Function). The core issue stems from WebSocket endpoints that do not implement proper authentication checks before allowing connections to be established. WebSocket connections, once established, maintain a persistent bidirectional communication channel between the client and server. When authentication is not enforced at the connection establishment phase, any network-accessible attacker can connect and interact with the endpoint.

The network-based attack vector with low complexity and no privileges required makes this vulnerability particularly dangerous in ICS/OT environments where WebSocket interfaces may control or monitor critical infrastructure components. Successful exploitation provides high impact to both confidentiality and integrity, with some availability impact as well.

Root Cause

The root cause of this vulnerability is the Missing Authentication for Critical Function (CWE-306). The WebSocket endpoint implementation fails to validate user identity or credentials during the connection handshake process. This occurs when developers either omit authentication logic entirely or implement it incorrectly, assuming that network segmentation or obscurity will provide sufficient protection.

In properly secured implementations, WebSocket connections should validate authentication tokens, session cookies, or other credentials before completing the connection upgrade from HTTP to WebSocket protocol. The absence of this critical security control creates the vulnerability.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker with network access to the vulnerable WebSocket endpoint can:

1. Initiate a WebSocket connection to the target endpoint
2. Complete the WebSocket handshake without providing any credentials
3. Once connected, send and receive messages through the established channel
4. Access sensitive data transmitted through the WebSocket connection
5. Execute unauthorized commands or actions depending on the endpoint's functionality

In ICS/OT environments, this could allow attackers to monitor industrial processes, modify control parameters, or exfiltrate sensitive operational data without any authentication barriers.

Detection Methods for CVE-2025-54816

Indicators of Compromise

• Unexpected WebSocket connections from unknown or unauthorized IP addresses
• Unusual patterns of WebSocket traffic volume or timing
• WebSocket connections established without corresponding authentication events in logs
• Anomalous commands or data requests through WebSocket channels

Detection Strategies

• Monitor network traffic for WebSocket upgrade requests (HTTP 101 Switching Protocols) to sensitive endpoints
• Implement logging for all WebSocket connection establishments and correlate with authentication events
• Deploy network intrusion detection rules to identify WebSocket connections to ICS/OT systems from unauthorized network segments
• Review application logs for WebSocket session activity without associated user authentication

Monitoring Recommendations

• Enable detailed logging on WebSocket endpoints to capture connection metadata including source IP, timestamp, and session duration
• Implement real-time alerting for WebSocket connections originating from outside trusted network zones
• Establish baseline metrics for normal WebSocket connection patterns to identify anomalous activity
• Monitor for reconnaissance activities such as WebSocket endpoint enumeration attempts

How to Mitigate CVE-2025-54816

Immediate Actions Required

• Implement authentication requirements on all affected WebSocket endpoints
• Restrict network access to WebSocket services using firewalls and network segmentation
• Review and audit all WebSocket implementations for proper authentication enforcement
• Consider disabling or blocking WebSocket endpoints until patches are applied in critical environments

Patch Information

Refer to the CISA ICS Advisory ICSA-26-022-08 for vendor-specific patch information and remediation guidance. The GitHub CSAF JSON File contains detailed advisory data in structured format.

Workarounds

• Implement network-level access controls to restrict WebSocket endpoint access to authorized systems only
• Deploy a reverse proxy or API gateway that enforces authentication before forwarding requests to WebSocket endpoints
• Enable TLS/SSL for WebSocket connections (wss://) and implement certificate-based client authentication as a compensating control
• Segment ICS/OT networks to isolate vulnerable systems from untrusted network zones

The following network configuration demonstrates restricting WebSocket endpoint access using iptables as a temporary mitigation:

# Configuration example
# Restrict WebSocket port access to trusted IP ranges only
# Replace 8080 with your WebSocket port and adjust IP ranges accordingly

# Allow WebSocket connections from trusted management network
iptables -A INPUT -p tcp --dport 8080 -s 10.0.1.0/24 -j ACCEPT

# Allow WebSocket connections from authorized monitoring systems
iptables -A INPUT -p tcp --dport 8080 -s 192.168.100.0/24 -j ACCEPT

# Drop all other WebSocket connection attempts
iptables -A INPUT -p tcp --dport 8080 -j DROP

# Log dropped connection attempts for monitoring
iptables -A INPUT -p tcp --dport 8080 -j LOG --log-prefix "WS-BLOCKED: "