Pi-hole 6.5 fixes four high-severity flaws and migrates gravity.db

Pi-hole Core 6.5 is primarily a security hardening release: it patches four high-severity advisories (CVSS 7.8, 7.8, 7.8 and 7.3) and one low-severity issue (2.2), including command execution via a manipulated PID and root writing through a symlink. The gravity.db database migrates automatically to schema 21, and arpflush is replaced by networkflush.

• Four high-severity flaws rated CVSS 7.8, 7.8, 7.8 and 7.3
• gravity.db migrates automatically to schema 21 on upgrade
• arpflush removed; scripts and cron must switch to networkflush
• Debian 11 dropped from Pi-hole's CI test matrix