CVE-2026-26221 — AI Deep Analysis Summary

🚨 **Essence**: Unauthenticated .NET Remoting exposure in OnBase Workflow Timer Service. 💥 **Consequences**: Unsafe object deserialization → Arbitrary File Read/Write → **Remote Code Execution (RCE)**.

🛡️ **Root Cause**: **CWE-502** (Deserialization of Untrusted Data). The service exposes .NET Remoting without authentication, allowing attackers to inject malicious payloads.

🏢 **Affected**: **Hyland OnBase**. Specifically the **OnBase Workflow Timer Service**. Vendor: Hyland Software.

💀 **Attacker Capabilities**: Full system compromise. Can read/write arbitrary files and execute **arbitrary code** remotely. High impact on Confidentiality, Integrity, and Availability.

⚡ **Exploitation Threshold**: **LOW**. **No Authentication** required. **Low Complexity**. Network accessible (AV:N). Easy to exploit.

🔓 **Public Exploit**: **YES**. PoC available on GitHub: `CVE-2026-26221-Hyland-OnBase-Timer-Service-Unauthenticated-RCE`. Wild exploitation risk is high.

🔍 **Self-Check**: Scan for exposed **.NET Remoting** ports/services on the Workflow Timer Service. Look for unauthenticated endpoints accepting serialized objects.

🩹 **Official Fix**: **YES**. Hyland released a security update (Bulletin OB2025-03). Check vendor advisory for patching instructions.

🚧 **No Patch?**: **Mitigation**: Block network access to the Workflow Timer Service. Disable .NET Remoting if possible. Restrict permissions. **Isolate** the component.

🔥 **Urgency**: **CRITICAL**. CVSS **9.8** (High). Unauthenticated RCE with public PoC. **Patch Immediately** or isolate the service.