CVE-2025-8320: Tesla Wall Connector Firmware RCE Flaw

CVE-2025-8320 Overview

CVE-2025-8320 is a remote code execution vulnerability in the Tesla Wall Connector electric vehicle charging station. The flaw resides in the HTTP Content-Length header parser, which fails to validate user-supplied input before performing buffer operations. Network-adjacent attackers can trigger memory access past the end of an allocated buffer without authentication. Successful exploitation grants code execution in the context of the device firmware. The Zero Day Initiative tracked this issue as ZDI-CAN-26300 and assigned it advisory ZDI-25-711. The weakness is classified under [CWE-1284] Improper Validation of Specified Quantity in Input.

Critical Impact
An unauthenticated attacker on the adjacent network can execute arbitrary code on Tesla Wall Connector devices by sending a crafted HTTP request with a malformed Content-Length header.

Affected Products

Tesla Wall Connector hardware
Tesla Wall Connector firmware (all versions prior to vendor fix)
Deployments exposing the device HTTP interface on local Wi-Fi or Ethernet networks

Discovery Timeline

2025-07-30 - CVE-2025-8320 published to the National Vulnerability Database
2026-06-17 - CVE-2025-8320 last modified in NVD

Technical Details for CVE-2025-8320

Vulnerability Analysis

The Tesla Wall Connector exposes an HTTP service used for configuration, status reporting, and firmware management. The service parses incoming HTTP requests including the Content-Length header, which declares the size of the request body. The vulnerable parser accepts attacker-controlled values from this header and uses them in subsequent buffer operations without bounds checking. This leads to out-of-bounds memory access during request processing.

Because the attack requires only network reachability and no credentials, any device on the same Wi-Fi or local network segment can issue the malicious request. Code execution occurs in the context of the firmware process handling HTTP, providing control over the charging station and its connected network surface.

Root Cause

The root cause is improper input validation of the HTTP Content-Length header value, mapped to [CWE-1284]. The firmware does not verify that the declared length matches the size of the allocated receive buffer or the actual data received. This mismatch produces out-of-bounds read or write conditions during memory operations tied to request body handling.

Attack Vector

The attack vector is Adjacent Network. An attacker must reach the device over the local network, typically by joining the same Wi-Fi access point or LAN segment. The attacker then sends an HTTP request to the Wall Connector's web service with a crafted Content-Length header. No prior authentication, user interaction, or elevated privileges are required. Technical details are documented in the Zero Day Initiative Advisory ZDI-25-711.

// No verified public exploit code is available.
// The vulnerability is triggered by an HTTP request containing
// a malformed Content-Length header value that bypasses bounds checks
// in the firmware's request parser.

Detection Methods for CVE-2025-8320

Indicators of Compromise

HTTP requests to Wall Connector IP addresses containing unusually large, negative, or malformed Content-Length header values
Unexpected outbound network connections originating from the charging station
Wall Connector device reboots, service crashes, or firmware integrity changes without an administrator action

Detection Strategies

Inspect local network traffic to Wall Connector hosts and alert on non-standard HTTP Content-Length values or oversized request bodies
Baseline normal HTTP traffic to the device and flag deviations such as new source IPs or new request paths
Monitor DHCP and ARP tables for unexpected devices joining the network segment that hosts the charger

Monitoring Recommendations

Place the Wall Connector on an isolated VLAN and forward network logs to a centralized SIEM for inspection
Capture full HTTP transaction metadata from the segment using a network sensor or wireless IDS
Alert on any management traffic to the device originating from non-administrator endpoints

How to Mitigate CVE-2025-8320

Immediate Actions Required

Confirm the Wall Connector is connected to Wi-Fi so it can receive the vendor firmware update automatically
Restrict network access to the device to a dedicated IoT VLAN with no client-to-client communication
Remove untrusted devices from any shared network segment with the charger until firmware is updated

Patch Information

Tesla addresses Wall Connector firmware issues through automatic over-the-air updates delivered to connected devices. Owners should verify the unit is online and running the latest firmware version reported in the Tesla mobile application. Refer to the Zero Day Initiative Advisory ZDI-25-711 for vendor coordination details.

Workarounds

Disable or limit the Wall Connector's HTTP management interface exposure where the firmware permits
Apply Wi-Fi access controls so only trusted administrator devices can reach the charger's IP address
Use network segmentation and firewall rules to block adjacent-network access from guest or untrusted SSIDs

bash

# Example: isolate the Wall Connector on a dedicated VLAN (vendor-neutral)
# Replace interface and VLAN identifiers with values appropriate to your environment
ip link add link eth0 name eth0.50 type vlan id 50
ip addr add 192.0.2.1/24 dev eth0.50
ip link set dev eth0.50 up
iptables -A FORWARD -i eth0.50 -o eth0 -j DROP
iptables -A FORWARD -s 192.0.2.0/24 -d 192.0.2.0/24 -j DROP