CVE-2022-44253 is a high-severity vulnerability identified in the TOTOLINK LR350 router firmware version 9.3.5u.6369_B20220309. The issue is a post-authentication buffer overflow occurring in the setDiagnosisCfg function, specifically triggered via the 'ip' parameter. Buffer overflow vulnerabilities arise when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory. In this case, the vulnerability requires an attacker to have authenticated access to the device, meaning they must already possess valid credentials or have exploited another vector to gain limited access. Once authenticated, an attacker can send a specially crafted request to the setDiagnosisCfg function, causing a buffer overflow that can lead to arbitrary code execution, denial of service, or system compromise. The CVSS 3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability (all rated high), with network attack vector, low attack complexity, and no user interaction required. The scope is unchanged, meaning the vulnerability affects only the vulnerable component. No public exploits are currently known in the wild, and no official patches or vendor advisories have been published at the time of this analysis. The vulnerability is categorized under CWE-787 (Out-of-bounds Write), a common and critical software weakness that can lead to serious security breaches if exploited. TOTOLINK LR350 is a consumer and small office/home office (SOHO) wireless router, commonly used for internet connectivity and network management. The setDiagnosisCfg function is likely related to diagnostic or configuration settings, which if manipulated, can compromise device stability and security. Given the post-authentication requirement, exploitation is limited to insiders or attackers who have already bypassed initial access controls, but the impact of successful exploitation is severe, potentially allowing full device compromise and network pivoting.

For European organizations, especially small and medium enterprises (SMEs) and home users relying on TOTOLINK LR350 routers, this vulnerability poses a significant risk. Successful exploitation could allow attackers to execute arbitrary code on the router, leading to full device compromise. This can result in interception or manipulation of network traffic, disruption of internet connectivity, and use of the device as a foothold for lateral movement within the internal network. Confidential data passing through the router could be exposed or altered, impacting data confidentiality and integrity. Availability could be affected by denial-of-service conditions triggered by the overflow. Given the router's role as a network gateway, compromise could undermine the security of connected systems and sensitive information. Although the vulnerability requires authentication, attackers may leverage default or weak credentials, social engineering, or other vulnerabilities to gain initial access. The lack of known public exploits reduces immediate risk but does not eliminate it, as attackers may develop exploits over time. The absence of official patches increases exposure duration. Organizations in critical infrastructure sectors, financial services, and government entities using these devices in remote or branch offices may face elevated risks due to potential data breaches or service disruptions.

Immediately audit all TOTOLINK LR350 routers within the organization to identify affected firmware versions, specifically version 9.3.5u.6369_B20220309. Change default credentials and enforce strong, unique passwords to reduce the risk of unauthorized authentication. Restrict administrative access to the router’s management interface by limiting it to trusted IP addresses or via VPN, preventing unauthorized internal or external access. Disable remote management features if not required, minimizing exposure to network-based attacks. Implement network segmentation to isolate critical systems from devices that may be vulnerable or less secure. Monitor router logs and network traffic for unusual activity indicative of exploitation attempts, such as unexpected configuration changes or diagnostic commands. If possible, apply firmware updates or patches provided by TOTOLINK once available; in the absence of official patches, consider replacing vulnerable devices with models from vendors with active security support. Educate users and administrators on the risks of weak credentials and the importance of secure device management. Deploy intrusion detection/prevention systems (IDS/IPS) that can detect anomalous traffic patterns targeting router management interfaces. Regularly review and update network device inventories and security policies to ensure timely identification and remediation of vulnerabilities.