CVE-2021-39177

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.

• CWE-287

• https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6Patch, Third Party Advisory
• https://github.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858Patch, Third Party Advisory
• https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaYThird Party Advisory
• https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6Patch, Third Party Advisory
• https://github.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858Patch, Third Party Advisory
• https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaYThird Party Advisory

Published

Aug 30, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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