Is CVE-2026-45289 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-45289 being exploited in the wild.

How severe is CVE-2026-45289?

Medium severity, with a CVSS score of 5.3, published 2 June 2026.

Which products and versions are affected?

CloudburstMC Protocol < 3.0.0.Beta12-20260420.182526-15.

Is there a fix for CVE-2026-45289?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-45289 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-45289?

Check whether you run CloudburstMC Protocol at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-45289: CloudburstMC Protocol improper authentication in FULL type tokens

Q: Is there a fix for CVE-2026-45289?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-45289 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-45289?

Check whether you run CloudburstMC Protocol at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-45289 · Severity: medium · CVSS 5.3 · Published 2026-06-02

CloudburstMC Protocol is a software library used by Minecraft Bedrock Edition servers to communicate with players. A security flaw in how the library handles login information could allow unauthorized users to bypass certain identity checks. This could potentially lead to players joining servers with incorrect or spoofed identity information, affecting the integrity of player data and server management.

Vendors: CloudburstMC.

Quick answers

Is CVE-2026-45289 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-45289 being exploited in the wild.
How severe is CVE-2026-45289?: Medium severity, with a CVSS score of 5.3, published 2 June 2026.
Which products and versions are affected?: CloudburstMC Protocol < 3.0.0.Beta12-20260420.182526-15.
Is there a fix for CVE-2026-45289?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-45289 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-45289?: Check whether you run CloudburstMC Protocol at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An improper authentication vulnerability (CWE-287) exists in CloudburstMC Protocol due to insufficient validation of 'FULL' type authentication tokens. The flaw is located within the EncryptionUtils methods responsible for validating authentication payloads, specifically failing to properly verify the 'xid' and 'xname' fields. A remote, unauthenticated attacker can exploit this over the network to submit crafted authentication payloads that bypass intended identity verification. This impacts software relying on this library, such as the Geyser proxy. The issue is resolved in version 3.0.0.Beta12-20260420.182526-15.

Affected products

CloudburstMC Protocol < 3.0.0.Beta12-20260420.182526-15

Timeline

2026-05-12: advisory: GitHub Security Advisory published
2026-06-02: disclosed: NVD publication date

References

https://github.com/CloudburstMC/Protocol/security/advisories/GHSA-g2fr-c75x-4hf9

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