CVE-2026-4156 Overview
CVE-2026-4156 is a stack-based buffer overflow vulnerability affecting ChargePoint Home Flex EV chargers. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations without requiring authentication. The flaw exists within the handling of OCPP (Open Charge Point Protocol) messages, specifically in the getpreq function where user-supplied data is improperly validated before being copied to a fixed-length stack-based buffer.
Critical Impact
Successful exploitation enables attackers to execute arbitrary code with root privileges on vulnerable ChargePoint Home Flex EV chargers, potentially compromising the entire charging infrastructure and connected systems.
Affected Products
- ChargePoint Home Flex EV Chargers (specific versions not disclosed)
Discovery Timeline
- 2026-04-11 - CVE-2026-4156 published to NVD
- 2026-04-13 - Last updated in NVD database
Technical Details for CVE-2026-4156
Vulnerability Analysis
This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption flaw that occurs when a program writes more data to a stack-allocated buffer than it can hold. In the context of ChargePoint Home Flex devices, the vulnerability manifests in the OCPP message handling functionality.
The OCPP protocol is widely used for communication between EV charging stations and central management systems. The getpreq function within the charger firmware fails to properly validate the length of incoming user-supplied data before copying it to a fixed-length buffer allocated on the stack. This oversight allows an attacker to overflow the buffer with carefully crafted input.
Because the attack vector is adjacent network (requiring the attacker to be on the same network segment as the vulnerable device), exploitation requires proximity to the target device. However, once within range, no authentication is required to trigger the vulnerability, significantly lowering the barrier to exploitation. Successful exploitation results in code execution with root privileges, giving attackers complete control over the device.
Root Cause
The root cause of this vulnerability is improper input validation in the OCPP message parsing code. The getpreq handler accepts user-controlled data and copies it directly into a stack buffer without verifying that the data length does not exceed the buffer's capacity. This classic memory safety error allows attackers to overwrite adjacent stack memory, including return addresses and other critical control data.
Attack Vector
The attack requires network adjacency, meaning the attacker must have access to the same local network segment as the vulnerable ChargePoint Home Flex device. The attacker sends a specially crafted OCPP message to the charger containing oversized data in the getpreq request. When processed, this data overflows the stack buffer, corrupting the stack frame and allowing the attacker to redirect program execution to arbitrary code. The vulnerability can be exploited without authentication and results in code execution in the context of root.
For detailed technical information about this vulnerability, refer to the Zero Day Initiative Advisory ZDI-26-196.
Detection Methods for CVE-2026-4156
Indicators of Compromise
- Unusual or malformed OCPP messages targeting ChargePoint Home Flex devices
- Unexpected network traffic patterns on the local network segment where EV chargers are deployed
- Anomalous process execution or file system changes on the charging device
- Crash logs or error messages related to memory corruption in the OCPP handler
Detection Strategies
- Deploy network intrusion detection systems (NIDS) to monitor OCPP traffic for oversized or malformed messages
- Implement network segmentation to isolate EV charging infrastructure from general network traffic
- Monitor for unusual command execution or privilege escalation attempts on IoT devices
- Review firmware logs for signs of exploitation attempts or unexpected behavior
Monitoring Recommendations
- Enable logging on network devices to capture all traffic to and from EV chargers
- Implement anomaly detection for OCPP protocol communications
- Regularly audit network segments containing IoT devices for unauthorized access points
- Deploy SentinelOne Singularity to monitor endpoint behavior and detect exploitation attempts in real-time
How to Mitigate CVE-2026-4156
Immediate Actions Required
- Isolate ChargePoint Home Flex devices on a dedicated network segment with restricted access
- Implement strict network access controls to limit which devices can communicate with EV chargers
- Monitor for any exploitation attempts using the detection strategies outlined above
- Contact ChargePoint support for guidance on available patches or firmware updates
Patch Information
Patch information has not been publicly disclosed at this time. Organizations should monitor the Zero Day Initiative Advisory ZDI-26-196 and ChargePoint's official channels for updates regarding security fixes.
Workarounds
- Segment EV charging infrastructure onto isolated VLANs with strict firewall rules
- Restrict network access to only authorized management systems and personnel
- Disable remote OCPP connectivity if not required for operations
- Implement MAC address filtering to limit device access on the charging network
# Example network segmentation configuration (generic firewall)
# Create dedicated VLAN for EV charging infrastructure
# Restrict inbound access to management IPs only
iptables -A INPUT -i eth0 -s 192.168.10.0/24 -p tcp --dport 8080 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --dport 8080 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
