Hyland OnBase Workflow Timer Service up to 17.0.x Hyland.Core.Workflow.NTService.exe deserialization

Summaryinfo

A vulnerability described as very critical has been identified in Hyland OnBase Workflow Timer Service up to 17.0.x. This issue affects some unknown processing of the file Hyland.Core.Workflow.NTService.exe. Executing a manipulation can lead to deserialization. This vulnerability is registered as CVE-2026-26221. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in Hyland OnBase Workflow Timer Service up to 17.0.x and classified as very critical. This vulnerability affects an unknown code block of the file Hyland.Core.Workflow.NTService.exe. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was published by Victor A. Morales. The advisory is available at hyland.com. This vulnerability was named CVE-2026-26221 since 02/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 02/14/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• Hyland

Name

• OnBase Workflow Timer Service

Version

• 17.0

CPE 2.3info

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CPE 2.2info

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