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CVE-2026-123550: OpenAM Security Vulnerability

CVE-2026-123550 explained: critical Security Vulnerability in OpenAM. CVSS 9.3. Affected versions, detection, fixes and CTEM priority.

Last updated: Nov 8, 2026

CVSS
9.3 CRITICAL
EPSS
n/a
CISA KEV
Not listed
CWE
CWE-290

Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS

CVE-2026-123550 Overview

OpenAM before 16.1.4 contains an authentication bypass vulnerability in its SAML v2.0 service provider that accepts unsigned assertions on the ECP (PAOS) and HTTP-Artifact bindings when WantAssertionsSigned is false. Unauthenticated remote attackers can submit forged assertions to obtain sessions as any mapped user, including administrators, and hijack single sign-on to dependent applications.

Critical Impact

Remote, unauthenticated attackers can exploit this Security Vulnerability in OpenAM. The CVSS base score is 9.3 (Critical).

Affected Products

  • OpenAM: see the vendor advisory for the exact affected versions

Discovery Timeline

  • 2026-11-08: CVE-2026-123550 published to the National Vulnerability Database by disclosure@vulncheck.com
  • 2026-11-08: last updated in the NVD database

Technical Details for CVE-2026-123550

Vulnerability Analysis

CVE-2026-123550 is a Security Vulnerability weakness (CWE-290) in OpenAM. Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction.

With a CVSS base score of 9.3, apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Root Cause

The vendor description states: OpenAM before 16.1.4 contains an authentication bypass vulnerability in its SAML v2.0 service provider that accepts unsigned assertions on the ECP (PAOS) and HTTP-Artifact bindings when WantAssertionsSigned is false. Unauthenticated remote attackers can submit forged assertions to obtain sessions as any mapped user, including administrators, and hijack single sign-on to dependent applications.

Attack Vector

Based on the CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Attack complexity is low complexity.

No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.

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

Detection Methods for CVE-2026-123550

Detection Strategies

  • Inventory every instance of OpenAM and compare the running version with the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Run an authenticated vulnerability scan once your scanner ships a check for this CVE.

Monitoring Recommendations

  • Forward OpenAM application, access and audit logs to your SIEM for retrospective hunting.
  • Alert on new processes, configuration changes or outbound connections from the affected service.
  • Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.

How to Mitigate CVE-2026-123550

Immediate Actions Required

  • Apply the fixed version of OpenAM named in the vendor advisory.
  • Prioritize internet facing and business critical instances first.
  • Rescan after the change to confirm the exposure is closed.

Patch Information

Use the fixed version listed in the vendor advisory for OpenAM.

Workarounds

  • If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.

CWE References

Technical References

This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.

Frequently asked questions

CVE-2026-123550 is a critical severity Security Vulnerability in OpenAM with a CVSS score of 9.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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