CVE-2021-39177

HIGH

Geyser < 1.4.2-SNAPSHOT - Unauthenticated User Impersonation via Forged JWT Token

Title source: llm
STIX 2.1

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.

References (3)

Core 3

Scores

CVSS v3 7.4
EPSS 0.0143
EPSS Percentile 69.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Details

CWE
CWE-287
Status published
Products (2)
geysermc/geyser < 1.4.2
org.geysermc/connector 0 - 1.4.2-SNAPSHOTMaven
Published Aug 30, 2021
Tracked Since Feb 18, 2026