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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.

PUBLISHED Reserved 2026-02-11 | Published 2026-02-13 | Updated 2026-02-18 | Assigner VulnCheck




CRITICAL: 10.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Problem types

CWE-502 Deserialization of Untrusted Data

Product status

Default status
unaffected

8.0 (semver)
affected

Credits

Victor A. Morales, Senior Pentester Team Leader, GM Sectec, Corp. finder

VulnCheck coordinator

References

www.hyland.com/en/solutions/products/onbase product

community.hyland.com/...low-timer-service-bulletin-ob2025-03 vendor-advisory mitigation permissions-required

www.vulncheck.com/...rvices-unauthenticated-net-remoting-rce third-party-advisory

cve.org (CVE-2026-26221)

nvd.nist.gov (CVE-2026-26221)

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