ZDRES-232: resolveProxyClass Not Overridden - acceptMatchers Filter Bypass via java.lang.reflect.Proxy

Assessment: Fully addressed.

When the serialised stream contains a TCPROXYCLASSDESC (the marker for a java.lang.reflect.Proxy ), JDK’s ObjectInputStream.readProxyDesc() is dispatched. JDK then calls the default ObjectInputStream.resolveProxyClass(interfaces) implementation, which performs Class.forName(intf, false, latestUserDefinedLoader()) for EACH interface name and constructs the proxy class — bypassing the accepted classes list .

ZDRES-233: Class.forName(name, initialize=true, classLoader) in readClassDescriptor Triggers Static Initialiser of Allow-Listed Classes

Assessment: Fully addressed.

For ANY class on the allow-list, deserialising a stream that names it triggers the class’s (static initialiser) BEFORE any instance is constructed. This means an attacker who supplies a class name on the allow-list (e.g., the developer wrote accept(“com.myapp.") , attacker supplies com.myapp.SomeClass ) causes <clinit> of SomeClass — and many real-world classes have side-effecting static initialisers

Both issues have been fixed.

Last updated 18 June 2026

The fix for CVE-2026-41635 was not applied to the 2.1.X and 2.2.X branches. Here was the original issue 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 2.1.0 <= 2.1.11, and 2.2.0 <= 2.2.6.

The problem is resolved in Apache MINA 2.1.12, and 2.2.7 by applying the classname allowlist earlier.

Affected are applications using Apache MINA that call IoBuffer.getObject().

Applications using Apache MINA are advised to upgrade.