Impact pocketmine\entity\Skin does not correctly handle errors produced by adhocore/json-comment, which throws RuntimeException rather than returning false as PocketMine-MP expects. This leads to a server crash if the skin geometry data is invalid for some reason (e.g. a syntax error). Patches c9626c610b8f6810c8c987559c9197b2a291f0bb Workarounds A plugin could handle LoginPacket and PlayerSkinPacket to verify the skin geometry data can be parsed correctly, so that the error condition in the core code is …
Due to a workaround for unmapped network items implemented in 4.0.0-BETA5 (8ac16345a3bc099b62c1f5cfbf3b736e621c3f76), arbitrary item IDs are able to be written into an item's NBT. The intended purpose of this is to make said unmapped network items able to be moved around the inventory without issues. This led to an exploit due to internal limits on the range that item IDs can occupy (-32768 - 32767), while the tag type used …
This advisory duplicates another.
This advisory duplicates another.
PocketMine-MP caps maximum chat message length at 512 Unicode characters, or about 2048 bytes. No more than 2 chat messages may be sent per tick. However, due to legacy reasons, incoming chat message blobs are split by \n, and each part is treated as a separate message, the length of each part is individually checked. The length of the whole message is not checked. This leads to an exploitable performance …
When an inventory interaction is performed (e.g. moving an item around an inventory), the client sends a serialized version of the itemstack to the server, which the server then deserializes and compares against its own copy. If the copies don't match, the transaction is invalid. This involves deserializing item NBT from the client, which allows for bogus data to be provided. Usually, this is harmless, but in this particular case, …
This advisory duplicates another.
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.
Due to a workaround applied in 1.13, an attacker may send a negative damage/meta value in a tool or armour item's NBT, which TypeConverter then blindly uses as if it was valid without being checked. When this invalid metadata value reaches Durable->setDamage(), an exception is thrown because the metadata is not within the expected range for damage values. This can be reproduced with either a too-large damage value, or a …
This advisory duplicates another.
When handling form responses from the client (ModalFormResponsePacket), the Minecraft Windows client may send weird JSON that json_decode() can't understand. A workaround for this is implemented in InGamePacketHandler::stupid_json_decode(). An InvalidArgumentException is thrown by this function when it fails to fix an error found in the JSON, which is not caught by the caller. This leads to a server crash.
Impact Minecraft Bedrock authentication and its protocol encryption are inseparably linked. One is not complete without the other. This vulnerability affects servers which are able to be directly connected to via the internet (i.e. not behind a proxy). If you are using a proxy, please check that it supports protocol encryption and that it is enabled. Technical details Basics The client generates a private ECC key clientPriv which it uses …
This advisory duplicates another.
A remote attacker may crash a server by sending PlayerActionPacket with invalid facing values (e.g. negative), specifically with START_BREAK or CRACK_BLOCK actions, or with a UseItemTransactionData (typically in InventoryTransactionPacket).
This advisory duplicates another.
Impact Some skin data fields (e.g. skinID, geometryName) are not capped in length. These fields are typically saved in the NBT data of a player when the player quits the server, or during an autosave. This is problematic due to the 32767 byte limit on TAG_Strings. If any of these fields exceeds 32767 bytes, an exception will be thrown during data saving, which will cause the server to crash. Other …
Impact Players can fill book pages with as many characters as they like; the server does not check this. In addition, the maximum of 50 pages is also not enforced, meaning that players can create "book bombs". This causes a variety of problems: Oversized NBT on the wire costing excess bandwidth for server and client Server crashes when saving region-based worlds due to exceeding maximum chunk size of 1 MB …