A malicious client may send a MovePlayerPacket to the server whose position or rotation contains NaN or INF. Since neither the server nor vanilla client handles this properly, a number of interesting side effects come into play.
A patch for this was included in the 3.18.1 release: https://github.com/pmmp/PocketMine-MP/commit/fb20bb38327b4c08ee3976640cd0dd547388a638
Workarounds could be implemented as plugins using DataPacketReceiveEvent to block any inbound movement packets containing bogus values.
If you have any questions or comments about this advisory:
{
"github_reviewed_at": "2021-05-21T18:18:08Z",
"github_reviewed": true,
"severity": "HIGH",
"nvd_published_at": null,
"cwe_ids": [
"CWE-20"
]
}