CVE-2021-39177 HIGH

CVE-2021-39177: User impersonation due to incorrect handling of the login JWT

Vendor Geysermc
Product Geyser
Weakness CWE-287 · Improper authentication
Published August 30, 2021
Last update August 4, 2024
View on NVD All CVEs

CVSS base score

7.4/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

August 30, 2021 CVE published
August 4, 2024 Record updated