CVE-2026-121600

Summary

A stack-based buffer overflow in the MAC Filter Handler of TOTOLINK A950RG firmware v4.1.2cu.5268_B20221104 allows remote attackers to overwrite memory via the addEffect parameter in the setMacFilterRules function, leading to potential code execution or device crash.

Exploitability

Exploitation requires low privileges (authenticated user) and no user interaction; the exploit is publicly available.

Blast radius

Successful exploitation could allow full compromise of the device—including remote code execution, data exfiltration, or denial of service—with potential lateral movement to other devices on the same network.

Detection

Look for HTTP POST requests to /cgi-bin/cstecgi.cgi with abnormally long addEffect parameter values (e.g., >256 bytes) in web server or application logs; unauthenticated or unexpected access attempts to this endpoint may also be observable.

Prioritized remediation

Upgrade to firmware version 4.1.2cu.5268_B20221104_P1 or later if available; if no patched version is published, disable MAC filtering functionality and restrict access to /cgi-bin/cstecgi.cgi via network segmentation.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.