Pi-hole is a DNS sinkhole that protects devices from unwanted content without installing any client-side software. A vulnerability in versions prior to 5.18.3 allows an authenticated user to make internal requests to the server via the `gravity_DownloadBlocklistFromUrl()` function. Depending on some circumstances, the vulnerability could lead to remote command execution. Version 5.18.3 contains a patch for this issue.
https://github.com/pi-hole/pi-hole/security/advisories/GHSA-jg6g-rrj6-xfg6
https://github.com/pi-hole/pi-hole/commit/2c497a9a3ea099079bbcd1eb21725b0ed54b529d