PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-33439 OpenIdentityPlatform CVE debrief

CVE-2026-33439 is a pre-authentication Remote Code Execution (RCE) vulnerability in OpenAM, an access management solution. The vulnerability exists in OpenAM versions prior to 16.0.6 and allows an unauthenticated attacker to 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. This vulnerability bypasses the WhitelistObjectInputStream mitigation that was applied to the jato.pageSession parameter after CVE-2021-35464. Organizations should be aware of the potential risks associated with this vulnerability and take immediate action to upgrade to a patched version.

Vendor
OpenIdentityPlatform
Product
OpenAM
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-07
Original CVE updated
2026-07-24
Advisory published
2026-04-07
Advisory updated
2026-07-24

Who should care

Organizations using OpenAM versions prior to 16.0.6 should be aware of this vulnerability and take immediate action to upgrade to a patched version. Additionally, security teams and administrators responsible for managing access management solutions should be aware of the potential risks associated with this vulnerability.

Technical summary

The vulnerability exists due to unsafe Java deserialization of the jato.clientSession HTTP parameter in OpenAM. 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. This bypasses the WhitelistObjectInputStream mitigation that was applied to the jato.pageSession parameter after CVE-2021-35464.

Defensive priority

High

Recommended defensive actions

  • Upgrade to OpenAM version 16.0.6 or later
  • Implement additional security measures such as monitoring and incident response planning
  • Conduct a thorough review of the OpenAM configuration and ensure that all necessary security patches are applied
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-04-07T21:17:17.407Z and was last modified on 2026-07-24T23:10:00.563Z. The NVD entry is currently Analyzed. Evidence is limited to public sources and may not reflect the full scope of affected systems or potential impacts. Defenders should verify the vulnerability's existence and potential exposure within their environments.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-33439 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-33439

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-33439 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-33439

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.