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

7.4HIGH

Key Information:

Vendor

Geysermc

Status
Geyser
Vendor
CVE Published:
30 August 2021

What is 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.

Affected Version(s)

Geyser <= 1.4.1-SNAPSHOT

References

https://github.com/GeyserMC/Geyser/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7...
x_refsource_MISC
https://updates.playhive.com/weekend-maintenance-disclosu...
x_refsource_MISC

CVSS V3.1

Score:
7.4
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.