CVE-2026-26221CWE-502

Hyland OnBase Timer Service Unauthenticated .NET Remoting RCE

Critical · published February 13, 2026

CVSS v4.0
9.3
EPSS
2%
Percentile
75.8
In the wild
Unconfirmed
What it is

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 record
Technical detail
CVSS v4.0
9.3 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS
0.01615 · 75.8th percentile
Weakness
CWE-502 · Deserialization of Untrusted Data
Published
2026-02-13T15:21Z
EPSS history
Timeline
  • 13 FEB 15:21Z
    Hyland OnBase Timer Service Unauthenticated .NET Remoting RCE
    cvelistv5