Description
A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function fromAdvSetMacMtuWan of the file /goform/AdvSetMacMtuWan. The manipulation leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit is publicly available and might be used.
Published: 2026-01-29
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: Remote Code Execution
Action: Immediate Patch
AI Analysis

Impact

The vulnerability is a stack-based buffer overflow in the fromAdvSetMacMtuWan function located at /goform/AdvSetMacMtuWan in the firmware of Tenda AC21. This flaw allows an attacker to manipulate input to overflow a buffer on the stack, potentially leading to arbitrary code execution or denial of service. The problem is classified as a stack overflow (CWE-119) and buffer overrun (CWE-121).

Affected Systems

Tenda AC21 routers running firmware version 16.03.08.16 are affected. Devices with the AC21 model and the specified firmware build are the only ones listed as vulnerable. No other firmware versions or models are known to be affected at this time.

Risk and Exploitability

The CVSS score of 8.7 indicates a high severity vulnerability, and the EPSS score of less than 1% indicates a low probability of exploitation in the wild. The flaw is not currently listed in the CISA KEV catalog. Remote exploitation requires reaching the /goform/AdvSetMacMtuWan endpoint and sending a specially crafted payload that overflows the stack. Once executed, the payload could allow an attacker to run arbitrary commands with the privileges of the web interface, potentially compromising the entire device.

Generated by OpenCVE AI on April 18, 2026 at 01:15 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the firmware to the latest AC21 release that includes the stack‑buffer overflow fix.
  • Restrict access to the device’s web interface to trusted networks or IP addresses to reduce exposure to remote attackers.
  • As a temporary measure, block or filter requests to the /goform/AdvSetMacMtuWan endpoint on the router or at the network boundary to prevent the overflow exploit from being triggered.

Generated by OpenCVE AI on April 18, 2026 at 01:15 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Mon, 23 Feb 2026 09:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:tenda:ac21_firmware:*:*:*:*:*:*:*:*

Tue, 10 Feb 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Tenda ac21 Firmware
CPEs cpe:2.3:h:tenda:ac21:-:*:*:*:*:*:*:*
cpe:2.3:o:tenda:ac21_firmware:16.03.08.16:*:*:*:*:*:*:*
Vendors & Products Tenda ac21 Firmware

Mon, 02 Feb 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Fri, 30 Jan 2026 09:00:00 +0000

Type Values Removed Values Added
First Time appeared Tenda
Tenda ac21
Vendors & Products Tenda
Tenda ac21

Thu, 29 Jan 2026 22:45:00 +0000

Type Values Removed Values Added
Description A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function fromAdvSetMacMtuWan of the file /goform/AdvSetMacMtuWan. The manipulation leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit is publicly available and might be used.
Title Tenda AC21 AdvSetMacMtuWan fromAdvSetMacMtuWan stack-based overflow
Weaknesses CWE-119
CWE-121
References
Metrics cvssV2_0

{'score': 9, 'vector': 'AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR'}

cvssV3_0

{'score': 8.8, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R'}

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P'}

Subscriptions

Tenda Ac21 Ac21 Firmware
cve-icon MITRE

Status: PUBLISHED

Assigner: VulDB

Published:

Updated: 2026-02-23T09:07:49.829Z

Reserved: 2026-01-29T16:56:17.581Z

Link: CVE-2026-1637

cve-icon Vulnrichment

Updated: 2026-01-30T14:36:44.428Z

cve-icon NVD

Status : Analyzed

Published: 2026-01-29T23:16:11.473

Modified: 2026-02-10T15:13:38.820

Link: CVE-2026-1637

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-18T01:30:16Z

Weaknesses