Impact
DyeColorIdMap->fromId() did not account for the possibility that it might be given invalid input. This means that an undefined offset error would occur whenever this happened.
This code is indirectly called during Banner->deserializeCompoundTag(), which is invoked when deserializing any item NBT, whether from network or disk.
An attacker could use this bug to crash a server by providing NBT with invalid values for pattern colours in an inventory transaction, or by using /give to obtain an item with NBT like this.
Patches
08b9495
Workarounds
This is quite difficult to work around via a plugin. Theoretically, it's possible to override the Banner item class from a plugin and validate the data before it reaches deserializeCompoundTag().
For more information
If you have any questions or comments about this advisory:
Impact
DyeColorIdMap->fromId()did not account for the possibility that it might be given invalid input. This means that an undefined offset error would occur whenever this happened.This code is indirectly called during
Banner->deserializeCompoundTag(), which is invoked when deserializing any item NBT, whether from network or disk.An attacker could use this bug to crash a server by providing NBT with invalid values for pattern colours in an inventory transaction, or by using
/giveto obtain an item with NBT like this.Patches
08b9495
Workarounds
This is quite difficult to work around via a plugin. Theoretically, it's possible to override the
Banneritem class from a plugin and validate the data before it reachesdeserializeCompoundTag().For more information
If you have any questions or comments about this advisory: