CVE-2026-1157 is a buffer overflow vulnerability identified in the Totolink LR350 router firmware version 9.3.5u.6369_B20220309. The vulnerability resides in the setWiFiEasyCfg function of the /cgi-bin/cstecgi.cgi endpoint, where the ssid parameter is improperly validated, allowing an attacker to overflow a buffer. This flaw can be exploited remotely without authentication or user interaction, as the vulnerable CGI script is accessible over the network. The buffer overflow can lead to arbitrary code execution or cause the device to crash, impacting confidentiality, integrity, and availability of the device and potentially the network it serves. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P) indicates network attack vector, low attack complexity, no privileges or user interaction required, and high impact on all security properties. Although no active exploitation has been reported, a public exploit exists, increasing the likelihood of attacks. The vulnerability affects a specific firmware version, so devices running this or older versions are vulnerable until patched. The lack of patch links suggests that a fix may not yet be publicly available, emphasizing the need for defensive measures. This vulnerability is critical for organizations relying on Totolink LR350 routers, especially those exposing management interfaces to untrusted networks.

For European organizations, exploitation of CVE-2026-1157 could lead to full compromise of affected Totolink LR350 routers, resulting in unauthorized access to internal networks, interception or manipulation of network traffic, and potential pivoting to other systems. This could disrupt business operations, cause data breaches, and impact critical infrastructure relying on these devices. The high severity and remote exploitability increase the risk of widespread attacks, especially in sectors with less mature patch management or network segmentation. Organizations with exposed or poorly secured router management interfaces are particularly vulnerable. The compromise of network infrastructure devices like routers can have cascading effects on confidentiality, integrity, and availability of enterprise networks, making this a significant threat for European enterprises, government agencies, and critical infrastructure providers.

1. Immediately inventory all Totolink LR350 devices and verify firmware versions; prioritize those running 9.3.5u.6369_B20220309 or earlier. 2. Apply vendor-supplied patches or firmware updates as soon as they become available. 3. If patches are not yet available, restrict access to router management interfaces by implementing network segmentation and firewall rules to limit access to trusted IPs only. 4. Disable remote management features or move them to secure VPN-only access. 5. Monitor network traffic for unusual activity targeting /cgi-bin/cstecgi.cgi or attempts to exploit the ssid parameter. 6. Employ intrusion detection/prevention systems with signatures for this vulnerability or exploit. 7. Educate network administrators about the vulnerability and ensure rapid incident response capabilities. 8. Consider replacing vulnerable devices if patching is not feasible or timely. 9. Regularly review and update router configurations to minimize attack surface.