Vulnerability Description
Hyland OnBase contains an unauthenticated .NET Remoting exposure in the OnBase Workflow Timer Service (Hyland.Core.Workflow.NTService.exe). An attacker who can reach the service can send crafted .NET Remoting requests to default HTTP channel endpoints on TCP/8900 (e.g., TimerServiceAPI.rem and TimerServiceEvents.rem for Workflow) to trigger unsafe object unmarshalling, enabling arbitrary file read/write. By writing attacker-controlled content into web-accessible locations or chaining with other OnBase features, this can lead to remote code execution. The same primitive can be abused by supplying a UNC path to coerce outbound NTLM authentication (SMB coercion) to an attacker-controlled host.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://community.hyland.com/resources/bulletins-and-notices/223223-security-upd
- https://www.hyland.com/en/solutions/products/onbase
- https://www.vulncheck.com/advisories/hyland-onbase-timer-services-unauthenticate
FAQ
What is CVE-2026-26221?
CVE-2026-26221 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Hyland OnBase contains an unauthenticated .NET Remoting exposure in the OnBase Workflow Timer Service (Hyland.Core.Workflow.NTService.exe). An attacker who can reach the service can send crafted .NET ...
How severe is CVE-2026-26221?
CVE-2026-26221 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-26221?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.