OpenIdentityPlatform OpenAM: Pre-Authentication Remote Code Execution via jato.clientSession Deserialization in OpenAM

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-33439: 9.33% estimated exploitation activity in the next 30 days; percentile 95.39 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary OpenIdentityPlatform OpenAM 16.0.5 (and likely earlier versions) 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). --- Vulnerability Details Background CVE-2021-35464 identified that the jato.pageSession HTTP parameter was deserialized without class filtering, allowing pre-auth RCE. OpenIdentityPlatform OpenAM mitigated this by introducing WhitelistObjectInputStream in ConsoleViewBeanBase.deserializePageAttributes(), which restricts jato.pageSession deserialization to a hardcoded whitelist of ~40…

Published by the source

7 Apr 2026, 15:45 UTC

Last modified by the source

7 Apr 2026, 22:16 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2cqq-rpvq-g5qj

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# Patch Next advisory brief: CVE-2026-33439

Advisory: OpenIdentityPlatform OpenAM: Pre-Authentication Remote Code Execution via `jato.clientSession` Deserialization in OpenAM
IDs: CVE-2026-33439, GHSA-2cqq-rpvq-g5qj
Record: https://patchnext.com/advisories/cve-2026-33439 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.openidentityplatform.openam:openam 16.0.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.openidentityplatform.openam:openam: affected <= 16.0.5; fixed in 16.0.6

## Suggested inspection (read-only)
- Maven org.openidentityplatform.openam:openam: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.openidentityplatform.openam:openam.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2cqq-rpvq-g5qj (GitHub-reviewed advisory GHSA-2cqq-rpvq-g5qj lists affected ranges: Maven org.openidentityplatform.openam:openam >=0 <=16.0.5)

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