CVE-2022-42087 is a vulnerability identified in the Tenda AX1803 router model (specifically US_AX1803v2.0br_v1.0.0.1_2994_CN_ZGYD01_4 firmware version). The vulnerability is a Cross-Site Request Forgery (CSRF) issue affecting the function 'fromSysToolReboot'. CSRF vulnerabilities allow an attacker to trick an authenticated user into submitting a forged HTTP request, which can cause the victim's browser to perform unwanted actions on a web application in which they are currently authenticated. In this case, the vulnerable function relates to rebooting the router remotely. The CVSS 3.1 base score is 6.5 (medium severity), with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no confidentiality or integrity impact (C:N/I:N), but high impact on availability (A:H). This means an unauthenticated attacker can induce a user to trigger a reboot of the router through a crafted web request, causing denial of service by interrupting network connectivity. There is no indication of known exploits in the wild, and no patches or vendor advisories are referenced. The vulnerability is categorized under CWE-352 (Cross-Site Request Forgery). The lack of vendor or product project details limits the scope of public information, but the affected device is a consumer-grade router model from Tenda, a company known for affordable networking equipment. The attack requires user interaction (the user must visit a malicious webpage or click a crafted link) but no authentication or privileges on the router are needed, making exploitation feasible in scenarios where users access untrusted websites while connected to the vulnerable router's network.

For European organizations, the primary impact of this vulnerability is availability disruption. If an attacker successfully exploits this CSRF vulnerability, they can cause routers to reboot unexpectedly, leading to temporary loss of network connectivity. This can disrupt business operations, especially for small and medium enterprises (SMEs) or branch offices relying on Tenda AX1803 routers for internet access. While the vulnerability does not compromise confidentiality or integrity, repeated or timed reboots could be used as a denial-of-service tactic to degrade productivity or interrupt critical communications. In environments where remote work or VoIP services depend on stable internet connections, such disruptions can have cascading operational impacts. Additionally, since the attack requires user interaction, organizations with employees who frequently browse the internet on devices connected to these routers are at risk. The lack of authentication requirement increases the threat surface, as attackers do not need credentials to attempt exploitation. However, the absence of known exploits in the wild and the medium severity rating suggest the threat is moderate but should not be ignored.

To mitigate this vulnerability, organizations should first verify if they are using the Tenda AX1803 router model with the affected firmware version. If so, they should check for firmware updates or patches from Tenda and apply them promptly once available. In the absence of official patches, organizations can implement the following practical measures: 1) Restrict access to the router's web management interface to trusted IP addresses or disable remote management features to reduce exposure. 2) Educate users about the risks of visiting untrusted websites or clicking suspicious links while connected to the corporate network, emphasizing the importance of safe browsing habits. 3) Employ network segmentation to isolate critical systems from general user networks, limiting the impact of potential router reboots. 4) Use network monitoring tools to detect unusual router reboots or connectivity interruptions that may indicate exploitation attempts. 5) Consider deploying web filtering or endpoint security solutions that can block malicious websites or scripts that might trigger CSRF attacks. 6) If feasible, replace vulnerable routers with models from vendors that provide timely security updates and have a stronger security track record. These steps go beyond generic advice by focusing on reducing attack surface, user awareness, and detection capabilities specific to this CSRF vulnerability.