Go to homepageCyberStrike

Menu

Star on GitHub · 3.2k
Sign inDownload

CVE-2021-39177

7.4 · HIGH

Geyser is a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition.

Published Aug 30, 2021CWE-287EPSS 1.43%

Overview

CVE-2021-39177 is a high-severity vulnerability. It was published on August 30, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6GitHubgithub.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858Refupdates.playhive.com/weekend-maintenance-disclosure-2kJMaYGitHubgithub.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6GitHubgithub.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858Refupdates.playhive.com/weekend-maintenance-disclosure-2kJMaY

How CyberStrike helps

Frequently asked questions

What is CVE-2021-39177?

CVE-2021-39177 is a high-severity vulnerability. It was published on August 30, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).

How severe is CVE-2021-39177?

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-39177?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-39177?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-39177 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related HIGH CVEs from 2021

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999