Pi-hole is a DNS sinkhole that protects devices from unwanted content without installing any client-side software. Prior to 6.5, gravity.sh checks file:// adlist readability with sudo -u pihole test -r but then allows curl, sometimes running as root, to normalize URL dot segments and open a different file. A pihole-readable decoy can therefore pass the check while curl reads a root-only target, and /proc/self paths can similarly resolve against different processes. Exploitation requires an administrator who can add adlists and can place a symlink and decoy on the filesystem. This issue is fixed in version 6.5.
https://github.com/pi-hole/pi-hole/security/advisories/GHSA-g63w-24cr-p3w6
https://github.com/pi-hole/pi-hole/releases/tag/v6.5
https://github.com/pi-hole/pi-hole/pull/6719
https://github.com/pi-hole/pi-hole/commit/14554737be53c392abffc69677f6b9df02ae7971