A critical stack overflow vulnerability in the Totolink LR350 router allows unauthenticated remote attackers to crash the device, leading to a complete denial of service.

The device is susceptible to a stack-based buffer overflow triggered by a malformed http_host parameter within the sub_426EF8 function. This flaw is exploitable by an unauthenticated attacker via a crafted network request.

The exploitation of this vulnerability results in a denial of service, rendering the affected network infrastructure unreachable. With a CVSS score of 7.5, the risk is classified as High due to the lack of required authentication and the ease of network-based exploitation. Business operations relying on this hardware for connectivity will face significant downtime until the device is manually recovered.

Immediate Action: Since an official patch is currently unknown, users should immediately isolate the affected LR350 routers from the public internet and restrict access to trusted administrative networks.

Proactive Monitoring: Security teams should monitor device logs for repeated crashes or unusual request patterns targeting the HTTP interface.

Compensating Controls: Deploy a Web Application Firewall or network access control list to filter and block malformed HTTP requests sent to the device management interface.

Public Exploit Available: Yes — a published proof-of-concept exists, as documented in the referenced security researcher's write-up.

Given the public availability of proof-of-concept code and the high potential for service disruption, immediate network-level mitigation is required. Administrators must restrict management access to the device until the manufacturer releases a firmware update that addresses the stack overflow in the identified function.