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7.4

Tenda A21 Router: Unsecured Remote Code Execution Risk

CVE-2026-2870
Summary

A security flaw in the Tenda A21 router's Quality of Service settings can allow an attacker to remotely execute malicious code, potentially taking control of the device. This could lead to unauthorized access to the network or disruption of services. Update the router's firmware to the latest version to protect against this risk.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software
VendorProductAffected versionsFix available
tenda a21_firmware 1.0.0.0 –
Original title
A security flaw has been discovered in Tenda A21 1.0.0.0. Affected by this issue is the function set_qosMib_list of the file /goform/formSetQosBand. The manipulation of the argument list results in...
Original description
A security flaw has been discovered in Tenda A21 1.0.0.0. Affected by this issue is the function set_qosMib_list of the file /goform/formSetQosBand. The manipulation of the argument list results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.
nvd CVSS2.0 9.0
nvd CVSS3.1 8.8
nvd CVSS4.0 7.4
Vulnerability type
CWE-119 Buffer Overflow
CWE-121 Stack-based Buffer Overflow
Published: 21 Feb 2026 · Updated: 12 Mar 2026 · First seen: 6 Mar 2026