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:
This does, however, require that an attacker obtain a writable book in the first place in order to exploit the problem.
The bug has been fixed in 3.26.5 and 4.0.5.
Ban writable books, or use a plugin to cancel PlayerEditBookEvent
to cancel the event if strlen(text) > 1024 || mb_strlen(text) > 256
.
If you have any questions or comments about this advisory: