OpenAM: WebAuthn Java deserialization RCE via ObjectInputFilter depth>1 bypass

Open Access Management (OpenAM) is an access management solution. Prior to 16.1.2, WebAuthnAuthentication.deserialize applies an ObjectInputFilter that allows every serialized object at depth greater than 1 and therefore constrains only an AuthenticatorImpl root object. A pre-authentication attacker can supply a userHandle whose serialized graph has a valid AuthenticatorImpl root and a nested gadget class, causing readObject or readResolve execution before the cast and assertion verification when a usable gadget is on the classpath. This bypasses the incomplete remediation for the earlier WebAuthn deserialization vulnerability. This issue is fixed in version 16.1.2.