How severe is CVE-2026-33439?

CVE-2026-33439 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-33439 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33439?

CVE-2026-33439 affects Openidentityplatform Openam. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33439?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-33439 have an EU (EUVD) identifier?

Yes. CVE-2026-33439 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19941.

When was CVE-2026-33439 published?

CVE-2026-33439 was published on 2026-04-07 and last updated on 2026-06-17.

CVE-2026-33439

CVE-2026-33439 is a critical-severity vulnerability in Openidentityplatform Openam with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 10% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.3
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-19941
Weakness: CWE-502
Affected product: Openidentityplatform Openam
Published: 2026-04-07
Last modified: 2026-06-17

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 <jato:form> tags (e.g., the Password Reset pages). This vulnerability is fixed in 16.0.6.

Frequently asked questions

What is CVE-2026-33439?: 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.
How severe is CVE-2026-33439?: CVE-2026-33439 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-33439 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33439?: CVE-2026-33439 affects Openidentityplatform Openam. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33439?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-33439 have an EU (EUVD) identifier?: Yes. CVE-2026-33439 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19941.
When was CVE-2026-33439 published?: CVE-2026-33439 was published on 2026-04-07 and last updated on 2026-06-17.

References

https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-2cqq-rpvq-g5qj

Affected products (1)

cpe:2.3:a:openidentityplatform:openam:*:*:*:*:*:*:*:*

More vulnerabilities in Openidentityplatform Openam

CVE-2023-37471 — Critical (CVSS 9.1): Open Access Management (OpenAM) is an access management solution that includes Authentication, SSO, Authorization,…
CVE-2022-34298 — Medium (CVSS 5.3): The NT auth module in OpenAM before 14.6.6 allows a "replace Samba username attack."

All CVEs affecting Openidentityplatform Openam →

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities

CVE-2026-41104 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Planetary Computer Pro allows an unauthorized attacker to disclose…
CVE-2026-43633 — Critical (CVSS 10.0): HestiaCP versions 1.9.0 through 1.9.4 contain a deserialization vulnerability in the web terminal component caused by a…
CVE-2026-33819 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Bing allows an unauthorized attacker to execute code over a network.
CVE-2026-20131 — Critical (CVSS 10.0): A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could…
CVE-2026-25632 — Critical (CVSS 10.0): EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water…
CVE-2025-14931 — Critical (CVSS 10.0): Hugging Face smolagents Remote Python Executor Deserialization of Untrusted Data Remote Code Execution Vulnerability.…

Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →