CVE-2026-22082 is a session fixation vulnerability classified under CWE-384, found in Tenda 300Mbps Wireless Router F3 and N300 Easy Setup Router models. The vulnerability stems from the routers' use of login credentials as the session identifier within their web-based administrative interface. This design flaw allows an attacker to intercept the session ID by capturing network traffic, especially if transmitted over unencrypted channels such as HTTP or unsecured Wi-Fi. Since the session ID is essentially the login credential, once intercepted, the attacker can hijack the authenticated session without needing to authenticate themselves or trick the user into interaction. This enables unauthorized access to the router’s administrative functions, including viewing or modifying sensitive configuration settings, potentially leading to network compromise or persistent backdoors. The affected firmware versions include multiple releases of F3 v3.0 (V12.01.01.41 through V12.01.01.55) and F3 v4.0 (V03.03.01.40). The CVSS 4.0 base score is 8.8, indicating high severity, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality (VC:H), with low impacts on integrity and availability. No patches or exploits in the wild are currently documented, but the vulnerability’s nature makes it a critical risk if exploited.

For European organizations, exploitation of this vulnerability could lead to unauthorized access to network routers, allowing attackers to alter network configurations, intercept or redirect traffic, and potentially establish persistent footholds within corporate networks. This could compromise confidentiality of internal communications and data, degrade network integrity by modifying routing or firewall rules, and impact availability if routers are misconfigured or disabled. Organizations relying on affected Tenda router models for branch offices, small business networks, or home office setups are particularly at risk. The vulnerability could also facilitate lateral movement within networks if attackers gain administrative access to routers. Given the high CVSS score and the lack of required authentication or user interaction, the threat is significant, especially in environments where network traffic is not adequately encrypted or monitored.

European organizations should immediately assess their network infrastructure to identify the presence of affected Tenda router models and firmware versions. Mitigation steps include: 1) Upgrading to the latest firmware versions once Tenda releases patches addressing this vulnerability; 2) If patches are unavailable, disable remote web administration interfaces or restrict access to trusted IP addresses only; 3) Enforce HTTPS for router administrative interfaces to prevent session ID interception; 4) Implement network segmentation to isolate router management interfaces from general user networks; 5) Monitor network traffic for suspicious session hijacking attempts or unusual administrative access patterns; 6) Educate network administrators about the risks of session fixation and encourage regular password changes; 7) Consider replacing vulnerable devices with models from vendors with stronger security postures if immediate patching is not feasible.