CVE-2026-26290: Ev.energy Auth Bypass Vulnerability

CVE-2026-26290 Overview

CVE-2026-26290 is a session hijacking vulnerability affecting the ev.energy electric vehicle charging platform. The WebSocket backend uses charging station identifiers to uniquely associate sessions but allows multiple endpoints to connect using the same session identifier. This implementation results in predictable session identifiers and enables session hijacking or shadowing, where the most recent connection displaces the legitimate charging station and receives backend commands intended for that station.

This vulnerability may allow unauthorized users to authenticate as other users or enable a malicious actor to cause a denial-of-service condition by overwhelming the backend with valid session requests.

Critical Impact

Attackers can hijack WebSocket sessions of legitimate EV charging stations, intercept backend commands, and potentially disrupt charging infrastructure operations or impersonate authorized stations.

Affected Products

• ev.energy ev.energy platform
• EV charging station management systems using the affected WebSocket backend
• Connected charging infrastructure relying on ev.energy services

Discovery Timeline

• 2026-02-27 - CVE-2026-26290 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-26290

Vulnerability Analysis

This vulnerability is classified under CWE-613 (Insufficient Session Expiration), indicating a fundamental flaw in how the WebSocket backend manages session identifiers for charging stations. The core issue stems from the system's reliance on predictable charging station identifiers as the sole mechanism for session association, combined with a lack of proper validation when multiple connections attempt to use the same identifier.

When a malicious actor connects to the WebSocket backend using a known or guessed charging station identifier, the system allows this connection to succeed and displaces the legitimate station's session. This "shadowing" behavior means the attacker's connection becomes the authoritative endpoint, receiving all backend commands originally intended for the legitimate charging station.

The network-based attack vector means exploitation requires no user interaction and can be performed remotely. The vulnerability affects confidentiality, integrity, and availability of the charging infrastructure—attackers can intercept sensitive commands, inject unauthorized responses, or simply disrupt service by repeatedly hijacking sessions.

Root Cause

The root cause of CVE-2026-26290 lies in the insufficient session management architecture of the WebSocket backend. The system uses charging station identifiers as the primary session key without implementing:

1. Cryptographically strong session tokens - The predictable nature of station identifiers makes them easily guessable or discoverable
2. Session binding validation - No verification that a connecting endpoint is the legitimate owner of a session identifier
3. Concurrent connection handling - The system allows session displacement rather than rejecting duplicate identifier connections
4. Session integrity checks - Missing mechanisms to detect and prevent unauthorized session takeover

Attack Vector

The attack can be executed remotely over the network by any attacker who can establish a WebSocket connection to the ev.energy backend. The exploitation process involves:

1. Reconnaissance - The attacker identifies or enumerates valid charging station identifiers through various means (brute force, information disclosure, or network observation)
2. Session Shadowing - The attacker initiates a WebSocket connection using a target station's identifier
3. Session Displacement - The backend accepts the new connection, displacing the legitimate station
4. Command Interception - The attacker receives backend commands intended for the legitimate station, potentially including sensitive operational data or control instructions
5. Denial of Service - Alternatively, the attacker can repeatedly connect with various identifiers to disrupt multiple charging stations or overwhelm the backend

The attack requires no authentication or special privileges, making it particularly dangerous for publicly accessible charging infrastructure.

Detection Methods for CVE-2026-26290

Indicators of Compromise

• Multiple WebSocket connections attempting to use the same charging station identifier within a short time window
• Sudden disconnection of legitimate charging stations followed by reconnection from different IP addresses
• Unusual patterns in backend command responses indicating session interception
• Geographic anomalies where station connections originate from unexpected locations

Detection Strategies

• Monitor WebSocket connection logs for duplicate session identifier usage and rapid connection cycling
• Implement alerting for charging stations that experience frequent unexpected disconnections
• Deploy network traffic analysis to identify connection patterns consistent with session hijacking attempts
• Cross-reference station connection IPs with known legitimate infrastructure addresses

Monitoring Recommendations

• Enable detailed logging of all WebSocket session establishment and termination events
• Implement real-time alerting for session displacement events where a new connection supersedes an existing one
• Monitor for volumetric anomalies that could indicate denial-of-service attempts via session flooding
• Track command delivery success rates to identify potential interception scenarios

How to Mitigate CVE-2026-26290

Immediate Actions Required

• Review and restrict network access to the WebSocket backend to known legitimate charging station IP ranges where possible
• Implement rate limiting on WebSocket connections per identifier to slow down session hijacking attempts
• Enable enhanced logging to capture detailed session management events for forensic analysis
• Contact ev.energy for vendor-specific guidance and patch availability

Patch Information

Organizations should consult the CISA ICS Advisory ICSA-26-057-07 for official remediation guidance. Additional technical details are available in the GitHub CSAF File. Contact ev.energy directly through their official website for information on security updates and patched versions.

Workarounds

• Implement network segmentation to isolate charging station communications from untrusted networks
• Deploy a Web Application Firewall (WAF) or API gateway with rules to detect and block suspicious connection patterns
• Use VPN or private network connectivity for charging station to backend communications where feasible
• Implement additional application-layer authentication independent of session identifiers as a defense-in-depth measure

# Example network segmentation configuration for charging infrastructure
# Restrict WebSocket backend access to known station IP ranges
iptables -A INPUT -p tcp --dport 443 -s 10.10.0.0/16 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP

# Enable connection rate limiting per source IP
iptables -A INPUT -p tcp --dport 443 -m connlimit --connlimit-above 5 -j REJECT