CVE-2026-33439
CriticalOpenIdentityPlatform OpenAM: Pre-Authentication Remote Code Execution via jato.clientSession Deserialization in OpenAM
Published Apr 7, 2026 · Updated Aug 12, 2026 · Also known as GHSA-2cqq-rpvq-g5qj
Key Facts
Patch in the next maintenance window- CVE-2026-33439 is a critical-severity vulnerability (CVSS 9.3 v4) affecting OpenAM (Openidentityplatform), org.openidentityplatform.openam:openam (maven).
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 8.4% probability of exploitation in the next 30 days.
- Fixed versions are available, including OpenAM 16.0.6, org.openidentityplatform.openam:openam 16.0.6.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
CVSS v4
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS (30-day exploit likelihood)
8.4%
Higher than 94.9% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
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Description
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 tags (e.g., the Password Reset pages). This vulnerability is fixed in 16.0.6.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| OpenAMOpenidentityplatform | >= < 16.0.6 | 16.0.6 |
| org.openidentityplatform.openam:openammaven | See advisory | 16.0.6 |
Patched Releases
OpenAM
16.0.6
org.openidentityplatform.openam:openam
16.0.6
Timeline
Publicly disclosed
Apr 7, 2026
Last updated
Aug 12, 2026
Weakness Type
- CWE-502 Deserialization of Untrusted Data
References
- advisoryGHSA advisory
- advisoryhttps://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33439.json
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-33439
- articlehttps://github.com/OpenIdentityPlatform/OpenAM/commit/014007c63cacc834cc795a89fac0e611aebc4a32
- articlehttps://github.com/OpenIdentityPlatform/OpenAM/releases/tag/16.0.6
FAQ
Common Questions.
Open Access Management (OpenAM) is an access management solution.
Affected: OpenAM (Openidentityplatform) versions >= < 16.0.6; org.openidentityplatform.openam:openam (maven). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including OpenAM 16.0.6, org.openidentityplatform.openam:openam 16.0.6.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
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