CVE-2026-45289 CloudburstMC Protocol: Partially missing validation for FULL type authentication tokens
Attackers can bypass authentication in Minecraft Bedrock Edition servers using this library due to missing validation for FULL type tokens.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-45289?
CVE-2026-45289 is a medium-severity authentication bypass vulnerability in CloudburstMC Protocol, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
CloudburstMC Protocol is a protocol library for Minecraft Bedrock Edition. Prior to version 3.0.0.Beta12-20260420.182526-15, CloudburstMC Protocol is partially missing validation for FULL type authentication tokens (Cloudburst/Protocol). This vulnerability impacts publicly accessible software depending on the affected versions of Protocol, specifically the EncryptionUtils methods to validate auth payloads for FULL type tokens. This issue has been patched in version 3.0.0.Beta12-20260420.182526-15.
Weakness: CWE-287
Which versions are affected by CVE-2026-45289?
How do I fix CVE-2026-45289?
No fix has been published for CVE-2026-45289 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-45289 being exploited?
There is no known exploitation of CVE-2026-45289 in the wild and no public exploit code.