OpenAM <16.0.6 RCE via unsafe Java deserialization of jato.clientSession
CVE-2026-33439 Published on April 7, 2026

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.

NVD

Weakness Type

What is a Marshaling, Unmarshaling Vulnerability?

The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.

CVE-2026-33439 has been classified to as a Marshaling, Unmarshaling vulnerability or weakness.


Affected Versions

OpenIdentityPlatform OpenAM Version < 16.0.6 is affected by CVE-2026-33439

Exploit Probability

EPSS
0.12%
Percentile
30.96%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.