What’s Vulnerable › Vulnerabilities

CVE-2026-26221: Hyland OnBase Timer Service Unauthenticated .NET Remoting RCE

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-13 · updated 2026-06-17
• Weakness: CWE-502

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.

Affected products

• Hyland OnBase Workflow Timer Service: from 8.0 through 17.0.0

References

• https://community.hyland.com/resources/bulletins-and-notices/223223-security-update-onbase-workflow-timer-service-bulletin-ob2025-03
• https://www.hyland.com/en/solutions/products/onbase
• https://www.vulncheck.com/advisories/hyland-onbase-timer-services-unauthenticated-net-remoting-rce

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