CVE-2024-42737 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-bin/cstecgi.cgi script, specifically within the delBlacklist function, which improperly sanitizes user input before passing it to operating system commands. This flaw allows an authenticated attacker to send crafted HTTP requests that inject arbitrary commands executed with the privileges of the web server process, potentially root or administrative level on the device. The vulnerability is remotely exploitable over the network without requiring user interaction or elevated privileges beyond authentication. The CVSS 3.1 score of 9.8 reflects the critical nature of this flaw, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and full impact on confidentiality (C:H), integrity (I:H), and availability (A:H). Exploiting this vulnerability could allow attackers to fully compromise the router, manipulate network traffic, create persistent backdoors, or launch further attacks on connected internal networks. No patches or mitigations have been officially released at the time of publication, and no known exploits are currently in the wild, but the high severity demands urgent attention from affected users and administrators.

The impact of CVE-2024-42737 is severe for organizations using TOTOLINK X5000r routers, particularly in environments where these devices serve as critical network gateways or manage sensitive traffic. Successful exploitation can lead to complete device takeover, allowing attackers to intercept, modify, or redirect network traffic, potentially compromising confidentiality and integrity of communications. Attackers could also disrupt network availability by disabling or destabilizing the router. Furthermore, compromised routers can serve as footholds for lateral movement into internal networks, increasing the risk of broader organizational breaches. The lack of required privileges beyond authentication and no need for user interaction lowers the barrier for exploitation, increasing the threat level. Organizations with exposed router management interfaces or weak authentication controls are especially vulnerable. The absence of known exploits currently provides a limited window for remediation before active exploitation emerges.

To mitigate CVE-2024-42737, organizations should immediately restrict access to the router’s management interface by implementing network segmentation and firewall rules to limit access only to trusted administrators. Enforce strong authentication mechanisms and change default credentials to prevent unauthorized access. Monitor network traffic and device logs for unusual activity indicative of exploitation attempts. Disable remote management features if not required. Since no official patch is currently available, consider temporarily replacing affected devices with alternative hardware or firmware versions not impacted by this vulnerability. Engage with TOTOLINK support channels to obtain updates on patches or firmware upgrades addressing this issue. Additionally, implement network intrusion detection systems (NIDS) to detect suspicious command injection attempts targeting the /cgi-bin/cstecgi.cgi endpoint. Regularly audit device configurations and firmware versions to ensure compliance with security best practices.