CVE-2022-51018: PocketMine-MP before 3.26.5 Input Validation via Book Pages
PocketMine-MP before 3.26.5 and 4.0.x before 4.0.5 does not limit book page text length, page count, or author/title length. A player who obtains a writable book can create oversized NBT ('book bombs'), causing excess bandwidth consumption and server crashes (exceeding the 1 MB chunk size limit when saving region-based worlds in PM3, or exceeding the 32 KiB TAGString limit in PM4).
Affected Software
Event History
Frequently Asked Questions
Which deployments are affected?
PocketMine-MP versions before 3.26.5 and 4.0.x versions before 4.0.5 are affected. The issue applies to servers using region-based worlds in PM3 and to PM4 servers that process oversized book string data.
What does an attacker need to exploit this?
An attacker needs player-level privileges sufficient to obtain a writable book. They can then create a book with excessive page text, page counts, or author and title lengths.
What is the practical impact?
Oversized book NBT can consume excessive bandwidth and crash the server. In PM3, saving can exceed the 1 MB chunk size limit for region-based worlds; in PM4, book data can exceed the 32 KiB TAG_String limit.