Executive brief
The Tenda HG10 router contains a web server component vulnerable to buffer overflow when processing login requests. An unauthenticated attacker can send a specially crafted HTTP request with an oversized username parameter to crash the device or potentially execute arbitrary code, disrupting network connectivity for all users relying on that router.
Technical details
A buffer overflow vulnerability exists in the Boa Web Server's formLogin function (/boaform/formLogin) within the Tenda HG10 router. The vulnerability arises from unsafe handling of the username parameter, which is copied into a fixed-size buffer using strcpy() without length validation. An attacker can craft an HTTP POST request to /boaform/formLogin with an oversized username parameter, causing a stack buffer overflow. No authentication is required; the attack is remotely exploitable over the network. Exploitation has been demonstrated to cause denial-of-service (device crash), and depending on memory layout and runtime protections, could potentially enable arbitrary code execution. The vulnerability affects firmware version 300001138 and has been publicly disclosed with proof-of-concept code available.
Affected products
- Tenda HG10 HG7_HG9_HG10re_300001138
Timeline
- 2026-09-03: disclosed: Publicly disclosed via GitHub and NVD
- 2026-09-03: other: CVE-2026-85109 assigned