GHSA-h77f-xxx7-4858
HIGHUser impersonation due to incorrect handling of the login JWT
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
org.geysermc:connectorReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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:
- Come talk to us over on our Discord server in the #development channel
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.geysermc:connector | all versions | 1.4.2-SNAPSHOT |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.geysermc:connector. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.geysermc:connector to 1.4.2-SNAPSHOT or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h77f-xxx7-4858 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-h77f-xxx7-4858 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-h77f-xxx7-4858. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-h77f-xxx7-4858 in your dependencies?
O3 detects GHSA-h77f-xxx7-4858 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.