CVE-2021-39177: Improper Authentication

September 7, 2021

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.

References

github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6
github.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858
github.com/advisories/GHSA-h77f-xxx7-4858
nvd.nist.gov/vuln/detail/CVE-2021-39177

Code Behaviors & Features

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