Deserialization in Minecraft

CVE-2021-33790

The RebornCore library before 4.7.3 allows remote code execution because it deserializes untrusted data in ObjectInputStream.readObject as part of reborncore.common.network.ExtendedPacketBuffer. An attacker can instantiate any class on the classpath with any data. A class usable for exploitation might or might not be present, depending on what Minecraft modifications are installed.

Vulnerability class: Insecure Deserialization

EPSS: 0.028 (85.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-33790?
CVE-2021-33790 is a critical-severity vulnerability in Minecraft, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2021-05-31.
How severe is CVE-2021-33790?
Critical severity. CVSS v3 base score is 9.8 out of 10.