CVE-2024-7213 Overview
CVE-2024-7213 is a buffer overflow vulnerability in the TOTOLINK A7000R router running firmware version 9.1.0u.6268_B20220504. The flaw resides in the setWizardCfg function within /cgi-bin/cstecgi.cgi, where the ssid argument is copied into a fixed-size buffer without proper length validation [CWE-120]. Attackers with low-privilege authentication can trigger the overflow remotely across the network to corrupt memory on the device. Public exploit details have been disclosed, and the vendor did not respond to disclosure attempts.
Critical Impact
Remote authenticated attackers can overflow a stack buffer through the ssid parameter, enabling memory corruption that may result in denial of service or arbitrary code execution on affected TOTOLINK A7000R routers.
Affected Products
- TOTOLINK A7000R router hardware
- TOTOLINK A7000R firmware version 9.1.0u.6268_B20220504
- Deployments exposing the /cgi-bin/cstecgi.cgi management interface
Discovery Timeline
- 2024-07-30 - CVE-2024-7213 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-7213
Vulnerability Analysis
The vulnerability affects the setWizardCfg handler in the TOTOLINK A7000R web management CGI binary cstecgi.cgi. This handler processes wizard-based configuration requests sent to the router's HTTP interface. The ssid parameter supplied by the client is copied into a fixed-size stack buffer without a bounds check, leading to a classic stack-based buffer overflow.
Because cstecgi.cgi runs with elevated privileges on the router, memory corruption within its process can influence execution flow across the device. An attacker who submits an overlong ssid value can overwrite adjacent stack data, saved registers, and the return address. Successful exploitation may lead to arbitrary code execution as the CGI process, crash of the management daemon, or persistent misconfiguration of wireless settings.
Root Cause
The root cause is missing input length validation on the ssid argument before it is written into a fixed-size buffer, categorized as CWE-120 (Buffer Copy without Checking Size of Input). The CGI code trusts client-supplied string length instead of enforcing the destination buffer boundary.
Attack Vector
The attack is delivered over the network to the router's HTTP management endpoint at /cgi-bin/cstecgi.cgi. The attacker requires low-privileged authentication to invoke setWizardCfg. Because exploit details are publicly disclosed on GitHub, attackers can reproduce the request payload directly. Refer to the GitHub IoT Vulnerability Documentation for technical details on the malformed request structure.
No verified exploit code is reproduced here. The vulnerability manifests when an oversized string is passed as the ssid parameter to the wizard configuration endpoint.
Detection Methods for CVE-2024-7213
Indicators of Compromise
- HTTP POST requests to /cgi-bin/cstecgi.cgi invoking the setWizardCfg topic with abnormally long ssid values.
- Repeated crashes, reboots, or watchdog restarts of the router's HTTP management service.
- Unexpected changes to wireless SSID configuration or wizard state after unauthenticated or low-privileged sessions.
Detection Strategies
- Inspect router HTTP access logs for requests to cstecgi.cgi containing topicurl=setWizardCfg and measure the length of the ssid field against expected maximums (32 bytes for standard SSIDs).
- Deploy network intrusion detection signatures that flag HTTP request bodies to cstecgi.cgi exceeding reasonable size thresholds.
- Correlate management-interface traffic with authentication events to identify low-privileged sessions performing configuration wizard actions.
Monitoring Recommendations
- Monitor egress from router management VLANs for outbound connections initiated by the router process, which may indicate post-exploitation command and control.
- Alert on any exposure of the TOTOLINK management interface to WAN-side or untrusted network segments.
- Track firmware versions across the fleet and flag devices remaining on 9.1.0u.6268_B20220504.
How to Mitigate CVE-2024-7213
Immediate Actions Required
- Restrict access to the router's HTTP management interface to trusted internal management networks only, using ACLs on upstream switches or firewalls.
- Disable remote WAN management on all TOTOLINK A7000R devices until a patch is available.
- Rotate administrative credentials to reduce the value of any captured low-privileged accounts required for exploitation.
- Inventory all TOTOLINK A7000R units running firmware 9.1.0u.6268_B20220504 and prioritize them for replacement or isolation.
Patch Information
No vendor patch has been published. According to the CVE record, TOTOLINK was contacted about this disclosure but did not respond. Organizations should monitor the VulDB entry #272784 and the vendor's support channels for future firmware updates. Where a supported firmware release is not forthcoming, plan device replacement with a currently maintained platform.
Workarounds
- Place affected routers behind an upstream firewall that blocks direct access to /cgi-bin/cstecgi.cgi from user and guest network segments.
- Enforce management access exclusively over a dedicated administrative VLAN reachable only from jump hosts.
- Where the wizard workflow is not required, disable or block the setWizardCfg endpoint via reverse proxy filtering rules that reject requests with ssid values longer than 32 bytes.
# Example upstream firewall rule blocking external access to the vulnerable CGI
iptables -I FORWARD -p tcp -d <router_ip> --dport 80 \
-m string --string "/cgi-bin/cstecgi.cgi" --algo bm -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
