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High

PocketMine-MP vulnerable to server crash with certain invalid JSON payloads in `LoginPacket` due to vulnerable dependency

  • Disclosed: 06.06.2023
  • Updated: 11.10.2026 10:22

Impact

An attacker could crash PocketMine-MP by sending malformed JSON in LoginPacket.

This happened due to a bug in netresearch/jsonmapper. The library wasn't doing proper checks when mapping JSON arrays and objects onto scalar model properties such as strings.

Patches

The problem was fixed in a fork of JsonMapper in dktapps/JsonMapper@a31902a31f5b6fdb832f57c0e3a3f16a3b41c012. PocketMine-MP releases 4.20.5 and 4.21.1 have been released with the fix.

Workarounds

  • Users of PocketMine-MP source installations may manually install the patched version of JsonMapper by backporting commit pmmp/PocketMine-MP@09668a37d66c6023685a948b7550c918620e98f2.
  • A plugin may also be able to workaround this issue by using DataPacketReceiveEvent to attempt detection of suspicious payloads. An ErrorException will be thrown in the crash case, which can be caught by plugins.

References

cweiske/jsonmapper#210

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package pocketmine/pocketmine-mp < 4.20.5, >= 4.21.0, < 4.21.1 4.20.5, 4.21.1

References

CVSS score 7.5/10
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
06.06.2023
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-pqp3-8rrw-g8vm - 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.

All (30) in the archive
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

Severity:
  1. PocketMine-MP: JSON decoding of unlimited size large arrays/objects in ModalFormResponse Handling
    High CVE-2026-86204 < 5.39.2 5.39.2
  2. PocketMine-MP: LogDoS by large complex unknown property logging in clientData in LoginPacket
    High · 7.5 CVE-2026-86201 < 5.41.1 5.41.1
  3. PocketMine-MP `ResourcePackDataInfoPacket` amplification vulnerability due to lack of resource pack sequence status checking
    High CVE-2025-71417 < 5.32.1 5.32.1
  4. PocketMine-MP server crash with certain invalid JSON payloads in `LoginPacket` due to dependency vulnerability (3rd time)
    High · 7.5 CVE-2024-58381 < 5.11.1 5.11.1
  5. PocketMine-MP BookEditPacket crash when inventory slot in the packet is invalid
    High · 7.5 CVE-2024-58380 < 5.11.2 5.11.2
  6. PocketMine-MP server crash with certain invalid JSON payloads in `LoginPacket` due to dependency vulnerability (again)
    High · 7.5 CVE-2023-54390 >= 5.0.0, < 5.3.1, < 4.23.1 5.3.1, 4.23.1
  7. PocketMine-MP server crash due to incorrect EC curve used for LoginPacket identityPublicKey
    High · 7.5 CVE-2023-54355 >= 5.2.0, < 5.3.1 5.3.1
  8. PocketMine-MP vulnerable to server crash using badly formatted sign NBT in BlockActorDataPacket
    High · 7.5 CVE-2023-54392 >= 4.20.0, < 4.22.3, >= 5.0.0, < 5.2.1 4.22.3, 5.2.1
  9. PocketMine-MP vulnerable to improperly checked dropped item count leading to server crash
    High · 7.5 CVE-2023-7332 < 4.18.1 4.18.1
  10. PocketMine-MP vulnerable to server crash with certain invalid JSON payloads in `LoginPacket` due to vulnerable dependency this entry
    High · 7.5 CVE-2023-54393 < 4.20.5, >= 4.21.0, < 4.21.1 4.20.5, 4.21.1
  11. PocketMine-MP has improperly handled dye colour IDs in banner NBT, leading to server crash
    High · 7.5 CVE-2023-54396 < 4.8.1 4.8.1
  12. PocketMine-MP invalid skin geometry JSON data leading to server crash
    High · 7.5 CVE-2022-51009 < 4.7.2 4.7.2
  13. Improperly checked IDs on itemstacks received from the client leading to server crash in PocketMine-MP
    High · 7.5 CVE-2022-51010 >= 4.0.0-BETA5, < 4.4.2 4.4.2
  14. Insufficient type validation in pocketmine/pocketmine-mp
    High · 7.5 CVE-2022-51012 < 4.2.9 4.2.9
  15. Improperly checked metadata on tools/armour itemstacks received from the client
    High · 7.5 CVE-2022-51013 < 4.2.4 4.2.4
  16. NaN/INF in serverbound movement packets can crash clients and servers
    High · 7.5 CVE-2021-48007 < 3.18.1 3.18.1
  17. Unhandled exception when decoding form response JSON
    High · 7.5 CVE-2022-51014 >= 4.0.0, < 4.0.7 4.0.7
  18. Unchecked validity of Facing values in PlayerActionPacket
    High · 7.5 CVE-2022-51015 < 4.0.6 4.0.6
  19. Uncapped length of skin data fields submitted by players
    High · 7.5 CVE-2022-51017 < 3.26.5, >= 4.0.0, < 4.0.5 3.26.5, 4.0.5
  20. Exploitable inventory component chaining in PocketMine-MP
    High CVE-2020-37277 < 3.15.4 3.15.4

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