CVE-2021-39177CWE-287

User impersonation due to incorrect handling of the login JWT

High · published August 30, 2021

CVSS v3.1
7.4
EPSS
1%
Percentile
72.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.4 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.01431 · 72.8th percentile
Weakness
CWE-287 · Improper Authentication
Published
2021-08-30T23:00Z
EPSS history
Timeline
  • 30 AUG 23:00Z
    User impersonation due to incorrect handling of the login JWT
    cvelistv5