Executive brief
The Tenda W3 wireless router, used for home and small office networking, contains a security flaw in its web management interface. By sending a specially crafted web request to the router, an attacker can cause the device to crash or reboot. This results in a denial of service, disrupting internet connectivity for all connected users and requiring a manual restart to restore operations.
Technical details
A stack-based buffer overflow vulnerability exists in the Tenda W3 router's CGI handler function FUN_00442b44 (formwrlSSIDset). The vulnerability is triggered when the application processes user-supplied HTTP parameters 'mit_ssid' and 'mis_ssid_index' via websGetVar. These values are subsequently passed to an unsafe sprintf call without proper bounds checking, leading to a buffer overflow on the stack. An unauthenticated remote attacker can exploit this by sending a crafted HTTP request with excessively long strings in these parameters. Successful exploitation results in a crash of the httpd service or a full device reboot, causing a Denial of Service.
Affected products
- Tenda W3 Wireless Router v1.0.0.3(2204)
Timeline
- 2026-03-15: other: CVE request submitted to MITRE
- 2026-06-06: disclosed: Public disclosure
- 2026-06-09: advisory: NVD published date