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Vulnerability record · CVE-2021-46393 · published 4 March 2022

CVE-2021-46393: Tenda ax3 firmware out-of-bounds write vulnerability

Tenda · Ax3 Firmware

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.

9.8 CVSS 3.1 Critical EPSS 16% · top 3.2% CWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score, v2 7.5
16%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/sec-bin/IoT-CVE/tree/main/Tenda/AX3/3 ExploitThird Party Advisory
https://github.com/sec-bin/IoT-CVE/tree/main/Tenda/AX3/3 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2025-69764Tenda ax3 firmware stack-based buffer overflow vulnerabilityTenda AX3 firmware v16.03.12.11 contains a stack-based buffer overflow in the formGetIptv function due to improper handling of the stbpvid stack buff…EPSS 1.1%9.8CVE-2025-69762Tenda ax3 firmware stack-based buffer overflow vulnerabilityTenda AX3 firmware v16.03.12.11 contains a stack overflow in formSetIptv via the list parameter, which can cause memory corruption and enable remote …EPSS 0.91%9.8CVE-2025-69763Tenda ax3 firmware stack-based buffer overflow vulnerabilityTenda AX3 firmware v16.03.12.11 contains a stack overflow in formSetIptv via the vlanId parameter, which can cause memory corruption and enable remot…EPSS 0.91%9.8CVE-2025-69766Tenda ax3 firmware stack-based buffer overflow vulnerabilityTenda AX3 firmware v16.03.12.11 contains a stack-based buffer overflow in the formGetIptv function due to improper handling of the citytag stack buff…EPSS 0.79%9.8CVE-2023-51812Tenda ax3 firmware command injection vulnerabilityTenda AX3 v16.03.12.11 was discovered to contain a remote code execution (RCE) vulnerability via the list parameter at /goform/SetNetControlList.EPSS 1.1%9.8CVE-2023-49408Tenda ax3 firmware out-of-bounds write vulnerabilityTenda AX3 V16.03.12.11 was discovered to contain a stack overflow via the function set_device_name.EPSS 0.92%9.8CVE-2023-49409Tenda ax3 firmware vulnerabilityTenda AX3 V16.03.12.11 was discovered to contain a Command Execution vulnerability via the function /goform/telnet.EPSS 1.5%9.8CVE-2023-27239Tenda ax3 firmware out-of-bounds write vulnerabilityTenda AX3 V16.03.12.11 was discovered to contain a stack overflow via the shareSpeed parameter at /goform/WifiGuestSet.EPSS 0.84%

Source: NIST National Vulnerability Database (record CVE-2021-46393), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.