Executive brief
A vulnerability exists in the Tenda W3 wireless router, a device used to provide internet connectivity in homes and small offices. An attacker can send a specially crafted web request to the router's management interface to cause the device to crash or reboot. This results in a denial of service, disrupting internet access for all connected users.
Technical details
A stack-based buffer overflow exists in the 'ask_to_reboot' CGI handler of Tenda W3V1.0BR firmware version v1.0.0.3(2204). The vulnerability is located in the 'ask_to_reboot' function, which is reachable via the wireless configuration handler (FUN_00449844). The handler retrieves the user-controlled HTTP parameter 'GO' using 'websGetVar' and passes it to 'ask_to_reboot'. Inside this function, the input is concatenated into a fixed-size stack buffer using an unbounded 'sprintf' call: 'sprintf(buf, "reboot.asp?page=%s", param_2)'. An attacker can exploit this by sending an excessively long string in the 'GO' parameter, leading to a crash of the 'httpd' process or a device reboot. While primarily a Denial of Service (DoS) risk, arbitrary code execution may be possible depending on the presence of exploit mitigations like stack canaries or ASLR.
Affected products
- Tenda W3 Wireless Router US_W3V1.0BR v1.0.0.3(2204)
Timeline
- 2026-03-04: other: CVE request submitted to MITRE
- 2026-06-06: disclosed: Public disclosure
- 2026-06-09: advisory: NVD published date