CVE-2026-33439: OpenIdentityPlatform OpenAM Java deserialization RCE in jato.clientSession

CVE-2026-33439 · Severity: critical · CVSS 9.8 · Published 2026-04-07

OpenAM is an identity and access management solution used to secure web applications and manage user sessions. A critical security flaw allows an unauthenticated attacker to remotely execute commands on the server by sending a specially crafted web request. This could lead to a total system takeover, theft of sensitive user credentials, and unauthorized access to protected corporate resources.

Technologies: Open Identity Platform OpenAM. Vendors: Maven, Open Identity Platform.

Quick answers

Is CVE-2026-33439 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33439 being exploited in the wild.
How severe is CVE-2026-33439?
Critical severity, with a CVSS score of 9.8, published 7 April 2026.
Which products and versions are affected?
org.openidentityplatform.openam:openam (Maven) ECOSYSTEM:introduced=0,fixed=16.0.6; Open Identity Platform OpenAM < 16.0.6.
Is there a fix for CVE-2026-33439?
Yes. org.openidentityplatform.openam:openam (Maven): upgrade to 16.0.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33439 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-33439?
Check whether you run org.openidentityplatform.openam:openam (Maven) or Open Identity Platform OpenAM at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • org.openidentityplatform.openam:openam (Maven): upgrade to 16.0.6 or later
    # set org.openidentityplatform.openam:openam to 16.0.6 in your pom.xml or build.gradle

Technical details

OpenIdentityPlatform OpenAM prior to version 16.0.6 is vulnerable to pre-authentication Remote Code Execution (RCE) due to unsafe Java deserialization (CWE-502). The vulnerability exists in the ClientSession.deserializeAttributes() method, which processes the 'jato.clientSession' HTTP parameter using ApplicationObjectInputStream without a class whitelist. This bypasses previous mitigations (CVE-2021-35464) that only addressed the 'jato.pageSession' parameter. An unauthenticated attacker can trigger the exploit by sending a crafted serialized Java object via GET or POST to any JATO ViewBean endpoint containing <jato:form> tags. Successful exploitation allows arbitrary OS command execution under the context of the application server user. The issue is resolved in version 16.0.6 by implementing WhitelistObjectInputStream filtering.

Affected products

  • OpenIdentityPlatform OpenAM < 16.0.6

Identifiers

  • CVE-2026-33439
  • GHSA-2cqq-rpvq-g5qj

Timeline

  • 2026-04-07: advisory: GitHub Security Advisory GHSA-2cqq-rpvq-g5qj published
  • 2026-04-07: disclosed
  • 2026-04-07: patched: Fixed in version 16.0.6

References

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