Sliver is a command and control framework that uses a custom Wireguard netstack. Prior to 1.6.11, a path traversal in the website content subsystem lets an authenticated operator read arbitrary files on the Sliver server host. This is an authenticated path traversal / arbitrary file read issue, and it can expose credentials, configs, and keys. This vulnerability is fixed in 1.6.11.
https://github.com/BishopFox/sliver/security/advisories/GHSA-2286-hxv5-cmp2
https://github.com/BishopFox/sliver/commit/818127349ccec812876693c4ca74ebf4350ec6b7