CVE-2026-22079 is a vulnerability classified under CWE-319, which pertains to the cleartext transmission of sensitive information. This flaw exists in specific Tenda wireless routers, namely the 300Mbps Wireless Router F3 and N300 Easy Setup Router, across several firmware versions (F3 v3.0 Firmware versions 12.01.01.41 through 12.01.01.55 and F3 v4.0 Firmware V03.03.01.40). The vulnerability arises because the routers transmit login credentials in plaintext during the initial login process or immediately following a factory reset via their web-based administrative interface. Since the credentials are not encrypted, any attacker positioned on the same local network segment can perform network traffic interception (e.g., via ARP spoofing or packet sniffing) to capture these credentials. This enables the attacker to gain unauthorized administrative access to the router, which could lead to further compromise of the internal network, including traffic manipulation, device configuration changes, or deployment of malicious firmware. The CVSS 4.0 vector indicates the attack requires local network access (AV:A), has low attack complexity (AC:L), requires no privileges (PR:N), no user interaction (UI:N), but results in high confidentiality, integrity, and availability impacts (VC:H, VI:H, VA:H). No authentication or user interaction is needed, increasing the risk. Currently, no patches or official fixes have been published, and no exploits have been reported in the wild. The vulnerability is particularly critical in environments where these routers are deployed in shared or untrusted networks, such as public Wi-Fi or multi-tenant buildings.

For European organizations, this vulnerability poses a significant risk to network security, especially for small and medium enterprises or home offices that rely on Tenda 300Mbps Wireless Router F3 and N300 Easy Setup Router models. Unauthorized access to the router can lead to interception and manipulation of internal network traffic, exposure of sensitive corporate data, and potential lateral movement within the network. In sectors with strict data protection regulations like GDPR, such unauthorized access could result in compliance violations and financial penalties. The vulnerability is particularly impactful in environments where multiple users share the same network segment, such as co-working spaces, hotels, or residential complexes. Additionally, critical infrastructure or public sector organizations using these devices may face increased risk of espionage or sabotage. The lack of encryption during credential transmission undermines trust in network perimeter defenses and could facilitate broader attacks if attackers gain persistent access to network devices.

Given the absence of official patches, European organizations should implement immediate compensating controls. First, isolate vulnerable Tenda routers on segmented networks to limit exposure to untrusted users and devices. Disable remote management features and restrict administrative access to trusted IP addresses only. Employ network monitoring tools to detect unusual access patterns or configuration changes on these routers. Where possible, replace affected devices with models from vendors that implement secure credential transmission protocols (e.g., HTTPS with TLS). Educate users about the risks of connecting to unsecured or shared networks where these routers are deployed. For environments requiring these routers, consider deploying VPNs or encrypted tunnels to protect management traffic. Regularly audit firmware versions and maintain an inventory of network devices to identify and prioritize vulnerable units. Stay alert for vendor updates or security advisories that may provide patches or firmware upgrades addressing this vulnerability.