cvedb.io
CVE-2021-39177
HIGH · CVSS 7.4
EPSS exploitation probability: 0%
Published 2021-08-30T23:15:07.070 · Last modified 2026-06-17T04:03:15.263

Summary

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 products

geysermc — geyser

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.