Impact
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 negative one.
Patches
c8e1cfcbee4945fd4b63d2a7e96025c59744d4f1
Workarounds
In theory this can be checked by plugins using a custom TypeConverter, but this is likely to be very cumbersome.
For more information
- Email us at team@pmmp.io