Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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


Assessment: Fully addressed.


When the serialised stream contains a TC_PROXYCLASSDESC (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.