The vulnerability occurs in the formDOMAINBLK function of Tenda routers running firmware 300001138_en_xpon. Manipulating the blkDomain argument can trigger a stack-based buffer overflow, which is a manifestation of CWE‑119 (Improper Restriction of Operations within the Bounds of a Buffer) and CWE‑121 (Stack-based Buffer Overflow). The description confirms that the attack can be performed remotely through the router’s web management interface.

Tenda HG7HG9 and HG10 routers with firmware 300001138_en_xpon are affected. The vulnerable endpoint is reachable at /boaform/formDOMAINBLK via the device’s HTTP interface.

The CVSS score of 9.3 indicates critical severity, and the EPSS score of 7% reflects a moderate likelihood of exploitation. The vulnerability is not listed in CISA KEV. No authentication requirement is mentioned, so the endpoint may be reachable without prior login. An attacker with network access to an exposed router could exploit the flaw remotely. The stack-based buffer overflow presents a serious risk due to its potential to disrupt normal device operation.