Critical severity · published Feb 13, 2026
CVE-2026-26221
Hyland OnBase Timer Service Unauthenticated .NET Remoting RCE
9.8
CVSS
1.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.3% · higher than 71% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OW
OnBase Workflow Timer Service · Hyland
8.0 through 17.0.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-26221
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-26221
community.hyland.com
https://community.hyland.com/resources/bulletins-and-notices/223223-security-update-onbase-workflow-timer-service-bulletin-ob2025-03
www.hyland.com
https://www.hyland.com/en/solutions/products/onbase
www.vulncheck.com
https://www.vulncheck.com/advisories/hyland-onbase-timer-services-unauthenticated-net-remoting-rce
