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GHSA-h77f-xxx7-4858

HighCVSS 7.4 / 10
Published Sep 7, 2021·Last modified Mar 13, 2026
Affected Components(0)

No affected components available

Description

Impact

<!--_What kind of vulnerability is it? Who is impacted?_-->

This allows anyone that can connect to the server to forge a LoginPacket with manipulated JWT token allowing impersonation as any Bedrock user. Unless credentials are saved in your configuration, online mode is not affected as users are still required to log in separately. If your credentials are saved, there is no risk of exposing your email or password.

Patches

<!--_Has the problem been patched? What versions should users upgrade to?_-->

This was patched as part of https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6 and https://github.com/GeyserMC/Geyser/commit/ab2f5b326fe590e09167e8b45b4b165ac06ecd13. if your Geyser version is 1.4.2-SNAPSHOT or later, the issue has been addressed on your build.

Workarounds

<!--_Is there a way for users to fix or remediate the vulnerability without upgrading?_-->

Geyser strongly recommends updating to fix this issue. If this isn't possible:

  • Use online mode and don't save credentials in your Geyser configuration
  • Use an additional authentication method on the Java server

References

<!--_Are there any links users can visit to find out more?_-->

This was disclosed to us by a staff member over at Hive; you can read their disclosure here: https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaY

For more information

If you have any questions or comments about this advisory:

Risk Scores
Base Score
7.4

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.

Threat Intelligence
6.8

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2021-39177
    Alias
  • EUVD-2021-2067
    Alias

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High severity
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