Pi-hole has a Local Privilege Escalation (post-compromise, pihole -> root).

Pi-hole is a Linux network-level advertisement and Internet tracker blocking application. Version 6.4 has a local privilege-escalation vulnerability allows code execution as root from the low-privilege pihole account. Important context: the pihole account uses nologin, so this is not a direct interactive-login issue. However, nologin does not prevent code from running as UID pihole if a Pi-hole component is compromised. In that realistic post-compromise scenario, attacker-controlled content in /etc/pihole/versions is sourced by root-run Pi-hole scripts, leading to root code execution. This vulnerability is fixed in 6.4.1.