Linksys E1000 devices through 2.1.02, E1200 devices before 2.0.05, and E3200 devices through 1.0.04 allow OS command injection via shell metacharacters in the apply.cgi ping_ip parameter on TCP port 52000.
https://thehackernews.com/2026/06/arystinger-malware-infects-4300-legacy.html
https://thehackernews.com/2025/01/hackers-exploit-zero-day-in-cnpilot.html
https://thehackernews.com/2025/01/mirai-botnet-variant-exploits-four.html
https://securityaffairs.com/172805/malware/gayfemboy-mirai-botnet-four-faith-flaw.html