Improperly checked IDs on itemstacks received from the client leading to server crash in PocketMine-MP
Impact
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 to represent the replacement IDs for unknown items is a TAG_Int, allowing a range from -(2^31) - 2^31 - 1. This leads to an uncaught exception which crashes the server.
Patches
5fd685e07d61ef670584ed11a52fd5f4b99a81a7
Workarounds
In theory this can be checked by plugins using a custom TypeConverter, but this is likely to be very cumbersome.
For more information
If you have any questions or comments about this advisory:
- Email us at team@pmmp.io
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | pocketmine/pocketmine-mp | >= 4.0.0-BETA5, < 4.4.2 | 4.4.2 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
-- Platform
- Composer
- Package
pocketmine/pocketmine-mp- Disclosed
- 07.06.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-fqx3-r75h-vc89 - CC BY 4.0
Vulnerability history: pocketmine/pocketmine-mp
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 30
- First → latest
- 11.2020 04.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 20
- Medium 8
- Low 2
Disclosures per year
- 2020: 1
- 2021: 1
- 2022: 11
- 2023: 8
- 2024: 2
- 2025: 2
- 2026: 5
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Improperly checked IDs on itemstacks received from the client leading to server crash in PocketMine-MP this entry
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