How severe is CVE-2021-46393?

CVE-2021-46393 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-46393 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-46393?

CVE-2021-46393 affects Tenda Ax3 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-46393?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-46393 published?

CVE-2021-46393 was published on 2022-03-04 and last updated on 2026-06-17.

CVE-2021-46393

CVE-2021-46393 is a critical-severity vulnerability in Tenda Ax3 Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 16% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 16% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Tenda Ax3 Firmware
Published: 2022-03-04
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-46393?: 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.
How severe is CVE-2021-46393?: CVE-2021-46393 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-46393 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-46393?: CVE-2021-46393 affects Tenda Ax3 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-46393?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-46393 published?: CVE-2021-46393 was published on 2022-03-04 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:o:tenda:ax3_firmware:16.03.12.10:*:*:*:*:*:*:*

More vulnerabilities in Tenda Ax3 Firmware

CVE-2025-69764 — Critical (CVSS 9.8): Tenda AX3 firmware v16.03.12.11 contains a stack-based buffer overflow in the formGetIptv function due to improper…
CVE-2025-69766 — Critical (CVSS 9.8): Tenda AX3 firmware v16.03.12.11 contains a stack-based buffer overflow in the formGetIptv function due to improper…
CVE-2025-69763 — Critical (CVSS 9.8): Tenda AX3 firmware v16.03.12.11 contains a stack overflow in formSetIptv via the vlanId parameter, which can cause…
CVE-2025-69762 — Critical (CVSS 9.8): Tenda AX3 firmware v16.03.12.11 contains a stack overflow in formSetIptv via the list parameter, which can cause memory…
CVE-2023-51812 — Critical (CVSS 9.8): Tenda AX3 v16.03.12.11 was discovered to contain a remote code execution (RCE) vulnerability via the list parameter at…
CVE-2023-49409 — Critical (CVSS 9.8): Tenda AX3 V16.03.12.11 was discovered to contain a Command Execution vulnerability via the function /goform/telnet.

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