CVE-2026-20781: Cloudcharge Auth Bypass Vulnerability

CVE-2026-20781 Overview

CVE-2026-20781 is a critical authentication bypass vulnerability affecting the CloudCharge cloudcharge.se electric vehicle (EV) charging infrastructure platform. WebSocket endpoints in the Open Charge Point Protocol (OCPP) implementation lack proper authentication mechanisms, enabling attackers to perform unauthorized station impersonation and manipulate data sent to the backend. An unauthenticated attacker can connect to the OCPP WebSocket endpoint using a known or discovered charging station identifier, then issue or receive OCPP commands as a legitimate charger.

Critical Impact

This vulnerability allows unauthenticated attackers to impersonate legitimate EV charging stations, potentially leading to privilege escalation, unauthorized control of charging infrastructure, and corruption of charging network data reported to the backend management systems.

Affected Products

• CloudCharge cloudcharge.se (all versions)
• OCPP WebSocket endpoint implementations within CloudCharge infrastructure
• Backend charging management systems connected to CloudCharge

Discovery Timeline

• February 27, 2026 - CVE-2026-20781 published to NVD
• March 5, 2026 - Last updated in NVD database

Technical Details for CVE-2026-20781

Vulnerability Analysis

This vulnerability is classified as CWE-306: Missing Authentication for Critical Function. The CloudCharge platform's OCPP WebSocket endpoints fail to implement proper authentication mechanisms, allowing any network-accessible attacker to establish connections without credentials. Given that no authentication is required, attackers can seamlessly impersonate legitimate charging stations by simply knowing or discovering valid station identifiers.

The OCPP (Open Charge Point Protocol) is the standard communication protocol between EV charging stations and central management systems. When WebSocket endpoints accepting OCPP connections lack authentication, the entire trust model between charging infrastructure and backend systems is compromised.

Root Cause

The root cause stems from missing authentication controls on the OCPP WebSocket endpoint. The system accepts WebSocket connections and processes OCPP commands based solely on the charging station identifier provided during connection establishment, without verifying the authenticity of the connecting client. This design flaw violates fundamental security principles requiring authentication before authorizing access to critical functions.

Attack Vector

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

1. Discover or enumerate valid charging station identifiers through reconnaissance
2. Establish a WebSocket connection to the OCPP endpoint using a legitimate station identifier
3. Issue OCPP commands as if they were the legitimate charging station
4. Intercept or manipulate charging session data, billing information, and operational commands
5. Potentially disrupt charging operations across the affected infrastructure

The attack does not require any prior privileges or user interaction, making it highly exploitable in network-accessible deployments.

Detection Methods for CVE-2026-20781

Indicators of Compromise

• Multiple WebSocket connections originating from unexpected IP addresses using the same charging station identifier
• Anomalous OCPP command sequences or commands issued during periods when physical charging stations should be inactive
• Geographic inconsistencies between charging station locations and connection source IPs
• Rapid connection/disconnection patterns to OCPP WebSocket endpoints

Detection Strategies

• Implement network traffic analysis to identify unauthorized WebSocket connections to OCPP endpoints
• Deploy behavioral analytics to detect anomalous charging station activity patterns
• Monitor for multiple simultaneous connections using identical station identifiers
• Correlate physical charging events with backend OCPP message logs to identify discrepancies

Monitoring Recommendations

• Enable detailed logging on all OCPP WebSocket endpoint connections including source IP and connection timestamps
• Implement alerting for connections from untrusted network ranges to charging infrastructure
• Monitor for unusual command patterns that deviate from normal charging station behavior
• Track charging session data integrity and flag discrepancies between reported and expected values

How to Mitigate CVE-2026-20781

Immediate Actions Required

• Restrict network access to OCPP WebSocket endpoints using firewall rules and network segmentation
• Implement IP whitelisting to allow connections only from known, legitimate charging station IP ranges
• Contact CloudCharge support for guidance on available security updates or configuration hardening
• Audit charging station identifiers and ensure they are not publicly disclosed or easily enumerable

Patch Information

Organizations should contact CloudCharge directly for information about security patches or firmware updates addressing this vulnerability. Refer to the CloudCharge Support Contact page for vendor communications. Additional technical details are available in the CISA ICS Advisory and the GitHub CSAF File.

Workarounds

• Deploy a VPN or secure tunnel requirement for all OCPP WebSocket communications until authentication is implemented
• Implement network-level access controls restricting OCPP endpoint access to known charging station networks only
• Consider deploying a reverse proxy with mutual TLS (mTLS) authentication in front of OCPP endpoints
• Enable rate limiting on WebSocket connections to reduce enumeration and brute-force attack effectiveness

# Example network segmentation using iptables
# Restrict OCPP WebSocket port access to known charging station subnet
iptables -A INPUT -p tcp --dport 9000 -s 10.100.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 9000 -j DROP

# Log unauthorized connection attempts for monitoring
iptables -A INPUT -p tcp --dport 9000 -j LOG --log-prefix "OCPP_UNAUTHORIZED: "