GHSA-fm35-jgg3-3grx NaN/INF in serverbound movement packets can crash clients and servers

• Packagist pocketmine/pocketmine-mp: < 3.18.1 → fixed in 3.18.1

Impact 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. • The server may crash in various ways if this exploit is used, because some mathematical operations on NaN/INF generate PHP warnings, which are converted into exceptions. • Clients may not be able to see other clients who have a NaN/INF rotation. • Clients may also crash in such cases. Patches A patch for this was included in the 3.18.1 release: https://github.com/pmmp/PocketMine-MP/commit/fb20bb38327b4c08ee3976640cd0dd547388a638 Workarounds Workarounds could be implemented as plugins using `DataPacketReceiveEvent` to block any inbound movement packets containing bogus values. For more information If you have any questions or comments about this advisory: • Open an issue in pmmp/PocketMine-MP • Email us at [email protected]