CVE-2026-33439: Pre-Authentication Remote Code Execution via `jato.clientSession` Deserialization in OpenAM

Open Access Management (OpenAM) is an access management solution. Prior to 16.0.6, OpenIdentityPlatform OpenAM is vulnerable to pre-authentication Remote Code Execution (RCE) via unsafe Java deserialization of the jato.clientSession HTTP parameter. This bypasses the WhitelistObjectInputStream mitigation that was applied to the jato.pageSession parameter after CVE-2021-35464. An unauthenticated attacker can achieve arbitrary command execution on the server by sending a crafted serialized Java object as the jato.clientSession GET/POST parameter to any JATO ViewBean endpoint whose JSP contains <jato:form> tags (e.g., the Password Reset pages). This vulnerability is fixed in 16.0.6.