CVE-2024-42740 is an OS command injection vulnerability identified in the TOTOLINK X5000r router firmware version 9.1.0cu.2350_b20230313. The vulnerability resides in the CGI script /cgi-bin/cstecgi.cgi, specifically in the setLedCfg function, which processes requests to configure LED settings on the device. Due to insufficient input validation or sanitization, authenticated attackers can craft malicious packets that inject arbitrary operating system commands. This allows attackers to execute commands with the privileges of the web server process, potentially leading to full system compromise. The vulnerability requires the attacker to be authenticated, indicating that initial access credentials or session hijacking is necessary. The CVSS v3.1 base score is 6.8, reflecting medium severity, with attack vector being adjacent network (AV:A), low attack complexity (AC:L), high privileges required (PR:H), no user interaction (UI:N), and impacts on confidentiality, integrity, and availability all rated high (C:H/I:H/A:H). No public exploits or patches have been reported at the time of publication, increasing the urgency for organizations to monitor and apply vendor updates once available. The vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), a common and critical class of injection flaws.

The impact of CVE-2024-42740 is significant for organizations deploying TOTOLINK X5000r routers, especially in environments where these devices manage critical network infrastructure. Successful exploitation allows attackers to execute arbitrary OS commands, potentially leading to full device takeover. This can result in unauthorized data access, network traffic interception or manipulation, disruption of network services, and pivoting to internal networks for further compromise. The requirement for authentication limits the attack surface but does not eliminate risk, as credentials may be obtained through phishing, credential reuse, or other means. The vulnerability affects confidentiality, integrity, and availability simultaneously, making it a high-risk issue for network security. Organizations relying on these routers for perimeter defense or internal segmentation could face severe operational and reputational damage if exploited.

To mitigate CVE-2024-42740, organizations should first verify if they are using the affected TOTOLINK X5000r firmware version 9.1.0cu.2350_b20230313. Until an official patch is released, administrators should restrict access to the router’s management interfaces to trusted networks and users only, employing network segmentation and firewall rules to limit exposure. Strong authentication mechanisms, such as multi-factor authentication, should be enforced to reduce the risk of credential compromise. Monitoring and logging of administrative access and unusual command execution attempts on the device should be implemented to detect exploitation attempts early. If possible, disable or restrict the vulnerable CGI endpoint or the setLedCfg functionality until a patch is available. Regularly check for firmware updates from TOTOLINK and apply them promptly once released. Additionally, consider replacing affected devices with models from vendors with more robust security track records if patching is delayed.