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CVE-2021-39177

HIGH CVSS: 7.4 Published: 2021-08-30 Modified: 2026-06-17

Description

Geyser is a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition. Versions of Geyser prior to 1.4.2-SNAPSHOT allow anyone that can connect to the server to forge a LoginPacket with manipulated JWT token allowing impersonation as any user. Version 1.4.2-SNAPSHOT contains a patch for the issue. There are no known workarounds aside from upgrading.

Affected Platforms

Geysermc Geyser

Weakness Type

CWE-287

References