CVE-2026-41635: Apache MINA: AbstractIoBuffer.resolveClass() null-clazz Branch Skips acceptMatchers Filter — Full Object Deserialization RCE

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-27 · updated 2026-10-26
Weakness: CWE-502

Description

Apache MINA's AbstractIoBuffer.resolveClass() contains two branches, one of them (for static classes or primitive types) does not check the class at all, bypassing the classname allowlist and allowing arbitrary code to be executed. The fix checks if the class is present in the accepted class filter before calling Class.forName(). Affected versions are Apache MINA 2.0.0 <= 2.0.27, 2.1.0 <= 2.1.10, and 2.2.0 <= 2.2.5. The problem is resolved in Apache MINA 2.0.28, 2.1.11, and 2.2.6 by applying the classname allowlist earlier. Affected are applications using Apache MINA that call IoBuffer.getObject(). Applications using Apache MINA are advised to upgrade.

Affected products

Apache Software Foundation Apache MINA: from 2.0.0 before 2.0.28; from 2.1.0 before 2.1.11; from 2.2.0 before 2.2.6 — fixed in 2.0.28, 2.1.11, 2.2.6

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache MINA 2.0.28, 2.1.11, 2.2.6. Check the vendor advisory for mitigations.

References

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