CVE-2026-7675 Overview
CVE-2026-7675 is a buffer overflow vulnerability in the Shenzhen Libituo Technology LBT-T300-HW1 router through firmware version 1.2.8. The flaw resides in the start_lan function within /apply.cgi, where the Channel and ApCliSsid parameters are not properly bounds-checked. Remote attackers with low-privilege access can manipulate these arguments to overflow buffers and compromise the device. The exploit has been publicly disclosed, and the vendor did not respond to disclosure attempts. The vulnerability is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer).
Critical Impact
Remote attackers can trigger a buffer overflow in /apply.cgi to compromise confidentiality, integrity, and availability of affected LBT-T300-HW1 routers. No vendor patch is available.
Affected Products
- Shenzhen Libituo Technology LBT-T300-HW1 router
- Firmware versions up to and including 1.2.8
- The start_lan function in /apply.cgi
Discovery Timeline
- 2026-05-03 - CVE-2026-7675 published to NVD
- 2026-05-04 - Last updated in NVD database
Technical Details for CVE-2026-7675
Vulnerability Analysis
The vulnerability exists in the start_lan function exposed through the /apply.cgi endpoint of the LBT-T300-HW1 web management interface. When the function processes the Channel and ApCliSsid HTTP parameters, it copies attacker-controlled input into fixed-size buffers without sufficient length validation. This results in adjacent memory corruption on the stack or heap.
Because the affected handler is reachable from the network interface, an authenticated attacker with minimal privileges can submit a crafted POST request and trigger the overflow. Successful exploitation can corrupt control data, leading to denial of service or arbitrary code execution within the router's web service context.
Root Cause
The root cause is improper restriction of operations within the bounds of a memory buffer [CWE-119]. The start_lan routine trusts the size of values supplied through the Channel and ApCliSsid parameters, performing copy operations such as strcpy or sprintf without enforcing maximum input length. This pattern is common in SOHO router firmware that reuses legacy CGI handlers.
Attack Vector
Exploitation requires network access to the router's HTTP management interface and a low-privilege session. The attacker submits a malicious request to /apply.cgi with an oversized Channel or ApCliSsid value. Because the LBT-T300-HW1 management interface is sometimes exposed to LAN clients or, in misconfigured deployments, to the internet, the attack surface extends beyond local administrators. Exploit details are publicly available through the VulDB Vulnerability #360828 entry and a GitHub Configuration Guide.
No verified proof-of-concept code is reproduced here. Refer to the VulDB Submission #800708 and VulDB Submission #800709 for technical artifacts.
Detection Methods for CVE-2026-7675
Indicators of Compromise
- Unexpected reboots or crashes of the LBT-T300-HW1 web service after requests to /apply.cgi.
- HTTP POST requests to /apply.cgi containing abnormally long Channel or ApCliSsid parameter values.
- New or modified configuration entries on the router that were not initiated by an administrator.
- Outbound traffic from the router to unfamiliar hosts following management interface activity.
Detection Strategies
- Inspect HTTP request bodies destined for the router for parameter lengths exceeding expected values (channels are single or two-digit integers; SSIDs are limited to 32 bytes).
- Deploy network intrusion detection signatures matching POST /apply.cgi requests with oversized Channel= or ApCliSsid= fields.
- Correlate router availability metrics with management plane traffic to identify exploitation-induced crashes.
Monitoring Recommendations
- Forward router syslog and HTTP access logs to a centralized logging platform for retention and search.
- Alert on repeated 4xx/5xx responses from /apply.cgi originating from a single source.
- Monitor management interface authentication for credential reuse, brute force, or unexpected logins from new IP addresses.
How to Mitigate CVE-2026-7675
Immediate Actions Required
- Restrict access to the router's web management interface to trusted administrative networks only and disable WAN-side administration.
- Rotate administrative credentials and disable any unused low-privilege accounts that could be leveraged to reach /apply.cgi.
- Place affected LBT-T300-HW1 devices behind network segmentation that limits exposure to untrusted clients.
- Evaluate replacing the device with a vendor-supported alternative, given the unresponsive disclosure outcome.
Patch Information
No vendor patch is available. According to the disclosure, Shenzhen Libituo Technology was contacted prior to publication but did not respond. Consult VulDB Vulnerability #360828 and the associated VulDB CTI for #360828 record for ongoing updates.
Workarounds
- Block external access to TCP ports hosting the router's HTTP/HTTPS management interface using upstream firewall rules.
- Place an inline web application firewall or reverse proxy in front of the management interface that enforces strict length limits on the Channel and ApCliSsid parameters.
- Disable the AP client (ApCli) feature if it is not required for the deployment, removing one path to the vulnerable code.
# Example upstream firewall rule to restrict router admin access
# Replace 192.0.2.0/24 with your administrative subnet
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s 192.0.2.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -s 192.0.2.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
