TRENDnet TEW-755AP mycli SSID Stack-Based Buffer Overflow (CVE-2026-76589)
First seen Aug 22, 2026 · Updated Aug 22, 2026 · CVSS 9.9
A critical stack-based buffer overflow exists in the mycli binary of TRENDnet TEW-755AP wireless access points, triggered by unsanitized input in the SSID parameter. The vulnerability is remotely exploitable and a public exploit is available, making it an immediate risk for exposed devices. CVSS 9.9 reflects the potential for full device compromise without authentication.
Technical Analysis
CVE-2026-76589 affects the FUN_401000 function within /sbin/mycli on TRENDnet TEW-755AP devices up to firmware version 20260702, where the ssid argument is copied into a fixed-size stack buffer without bounds checking, enabling a classic stack-based buffer overflow. Remote attackers can craft an oversized SSID value to overwrite return addresses and achieve arbitrary code execution or persistent denial of service on the access point. Because the exploit is publicly available, it lowers the barrier for mass scanning and automated exploitation against internet-facing or improperly segmented devices. Organizations deploying AI agent infrastructure on edge networks or branch offices using this access point are at risk of network-level compromise, which could allow attackers to intercept or manipulate traffic between agents and backend LLM/API services, exposing credentials, API keys, or tool-call data in transit.
Affected Systems
TRENDnet TEW-755AP wireless access points running firmware up to version 20260702; specifically the /sbin/mycli binary handling SSID configuration input
Indicators of Compromise
- File: /sbin/mycli
- Function: FUN_401000
- Affected parameter: ssid
Remediation Steps
- 1
Apply Firmware Update
Check TRENDnet's official support channels for a patched firmware release addressing this vulnerability and apply it immediately.
- 2
Restrict Remote Access
Disable remote/WAN-facing management interfaces on the TEW-755AP and restrict configuration access to trusted internal networks only.
- 3
Network Segmentation
Isolate vulnerable access points from critical infrastructure, including systems hosting AI agents or API gateways, using VLANs or firewall rules.
- 4
Monitor for Exploitation
Deploy IDS/IPS signatures for anomalous SSID configuration payloads and monitor device logs for crashes or unexpected reboots indicative of exploitation attempts.
- 5
Device Replacement
If no patch is available, consider decommissioning or replacing affected end-of-life TRENDnet devices with actively supported hardware.
CVE / Advisory IDs
Industries Most Exposed
Respond to this threat
Pro subscribers get a full AI-generated incident-response playbook for this threat — detection, containment, eradication, and recovery steps — plus an unlimited AI Threat Advisor for questions about your environment.