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.

Affected: Maven: org.openidentityplatform.openam:openam-auth-webauthn

### Summary The GHSA-6c99-87fr-6q7r fix wrapped WebAuthn authenticator deserialization in an `ObjectInputFilter` meant to allow only `AuthenticatorImpl`, but it short-circuits to `ALLOWED` for any object at stream `depth > 1`. Because the Java serialization filter is consulted for every class in the graph (and `depth == 1` only for the root's concrete class), the allowlist constrains only the root and leaves the entire nested graph unchecked.

### Impact An attacker can craft a stream rooted at `AuthenticatorImpl` with an arbitrary gadget chain nested inside. The gadget's `readObject`/`readResolve` executes during `readObject()` — before the cast and before any assertion verification — enabling remote code execution when a gadget is on the classpath. The deserialization sink is reached pre-authentication via an attacker-chosen `userHandle`.

Affected: Ubuntu:16.04:LTS: openam

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.