CVE-2021-27705: Tenda g1 Firmware

Critical severity, CVSS 9.8. EPSS: 2.9% chance of exploitation in the next 30 days.

Buffer Overflow in Tenda G1 and G3 routers with firmware v15.11.0.17(9502)_CN allows remote attackers to execute arbitrary code via a crafted action/"qosIndex "request. This occurs because the "formQOSRuleDel" function directly passes the parameter "qosIndex" to strcpy without limit.

Affected products

• Tenda g1 Firmware: version v15.11.0.17(9502)_cn only
• Tenda g3 Firmware: version v15.11.0.17(9502)_cn only

Published 2021-04-14. Last modified 2026-06-17.