Stack Buffer Overflow in Tenda AC11 Router (CVE‑2021‑31755) Enables Remote Code Execution
What It Is – Tenda AC11 Wi‑Fi routers contain a stack buffer overflow in the /goform/setmac endpoint. A crafted HTTP POST can overwrite the stack and allow an attacker to execute arbitrary code on the device.
Exploitability – The vulnerability is publicly disclosed (CVE‑2021‑31755) and a proof‑of‑concept exists. No public exploit‑as‑a‑service is known, but the attack requires only network access to the router’s management interface.
Affected Products – Tenda AC11 indoor/outdoor Wi‑Fi routers (all firmware versions prior to the vendor’s security update).
Why It Matters for Trust & Control Assurance
- Vulnerability Management – Demonstrates the need for continuous scanning, timely patching, and documented remediation to satisfy the “secure configuration” control objective that maps to many frameworks (e.g., NIST CSF, ISO 27001).
- Audit Evidence – Organizations must retain proof that the router firmware was updated and that the vulnerability was mitigated, providing a defensible audit trail.
- Supply‑Chain Assurance – Network‑infrastructure devices are often third‑party components; their security posture directly impacts the overall trust posture of the environment.
Recommended Actions
- Inventory all Tenda AC11 devices in your network.
- Apply the latest firmware released by Tenda that patches CVE‑2021‑31755.
- Validate the fix by testing the
/goform/setmacendpoint for proper handling of input. - Document the remediation in your vulnerability‑management system and retain firmware‑update logs as audit evidence.
Source: CISA KEV – CVE‑2021‑31755