CVE-2021-46393: tenda ax3_firmware Out-of-bounds Write

Vulnerability summary

CVE-2021-46393 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in tenda ax3_firmware. EPSS estimates a 15.92% chance of exploitation in the next 30 days, higher than 96.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 04-03-2022
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

There is a stack buffer overflow vulnerability in the formSetPPTPServer function of Tenda-AX3 router V16.03.12.10_CN. The v10 variable is directly retrieved from the http request parameter startIp. Then v10 will be splice to stack by function sscanf without any security check,which causes stack overflow. By POSTing the page /goform/SetPptpServerCfg with proper startIp, the attacker can easily perform remote code execution with carefully crafted overflow data.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.