Pterodactyl Wings SFTP write path does not enforce disk quota, allowing node-wide disk exhaustion

Wings is the server control plane for the Pterodactyl game-server management panel. In versions up to and including 1.13.2, the SFTP write path does not enforce a server's disk quota during a transfer, allowing a tenant with SFTP write access to a single server to exhaust the host node's physical disk and take down every server on it. Wings checks available space only once, as a boolean, when the write handle is opened, using a stale cached usage value and without knowing the size of the incoming data, and it then returns a raw, unaccounted file handle that is never re-checked as the transfer proceeds. A single upload can therefore be written without bound, far beyond the configured disk limit, until the node's disk is full, and because a server stopped for exceeding its limit is not treated as suspended, SFTP writes are still accepted even after the quota is already exceeded. This issue is fixed in version 1.13.3.

Quoted source text, attributed separately from HOL analysis.