GHSA-8jq6-w5cg-wm45 Exploitable inventory component chaining in PocketMine-MP

• Packagist pocketmine/pocketmine-mp: < 3.15.4 → fixed in 3.15.4

Impact Specially crafted `InventoryTransactionPacket`s sent by malicious clients were able to exploit the behaviour of `InventoryTransaction->findResultItem()` and cause it to take an abnormally long time to execute (causing an apparent server freeze). The affected code is intended to compact conflicting `InventoryActions` which are in the same `InventoryTransaction` by flattening them into a single action. When multiple pathways to a result existed, the complexity of this flattening became exponential. The problem was fixed by bailing when ambiguities are detected. At the time of writing, this exploit is being used in the wild by attackers to deny service to servers. Patches Upgrade to 3.15.4 or newer. Workarounds No practical workarounds are possible, short of backporting the fix or implementing checks in a plugin listening to `DataPacketReceiveEvent`. References c368ebb5e74632bc622534b37cd1447b97281e20 For more information If you have any questions or comments about this advisory: • Email us at [email protected]