CVEvulnerability

CVE-2021-39177

9.8 CRITICAL Published 2021-08-30 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-08-30
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.4 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1 ([email protected])
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 ([email protected])
7.5 HIGH — AV:N/AC:L/Au:N/C:P/I:P/A:P
Weaknesses
CWE-287

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.

Affected configurations

• geysermc geyser (< 1.4.2)

Related

Weakness · CWE (1)

  • CWE-287 Improper Authentication weakness

References