Loading vulnerability…
Hyland OnBase exposes unauthenticated .NET Remoting HTTP channel endpoints in the OnBase Workflow Timer Service (Hyland.Core.Workflow.NTService.exe) on TCP/8900 (e.g., TimerServiceAPI.rem and TimerServiceEvents.rem). An attacker with network reachability can send crafted .NET Remoting requests that trigger unsafe object unmarshalling (deserialization), resulting in arbitrary file read and arbitrary file write. The file-write primitive can be leveraged to achieve remote code execution by writing attacker-controlled content into web-accessible locations or by chaining with other OnBase features. The same behavior can also be abused by supplying a UNC path to coerce outbound NTLM authentication (SMB coercion) to an attacker-controlled host. The vendor also reported impact to the Workview Timer Service, but the affected version range is not defined in the provided content.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository contains a PoC exploit for CVE-2026-26221 targeting Hyland OnBase Workflow/Workview Timer Service. Structure: (1) README.md describing the vulnerability (unauthenticated .NET Remoting BinaryFormatter deserialization on TCP/8900) and usage flow; (2) poc_cve_2026_26221.py, a Python 3 script that guides the operator to start a listener, generates a PowerShell reverse-shell command, prints a ysoserial.net command to build a BinaryFormatter gadget payload (rev_shell.bin), then HTTP POSTs the raw payload bytes to the remoting endpoint. Core capability: unauthenticated network-based RCE by sending a crafted BinaryFormatter payload to http://<target>:8900/TimerServiceAPI.rem (or TimerServiceEvents.rem). The script sets headers mimicking .NET Remoting (User-Agent: ".NET Remoting", Content-Type: application/octet-stream, __RequestVerb: POST) and treats HTTP 200/500 as likely deserialization-triggered execution. Payload effect: PowerShell reverse shell callback to operator-specified lhost:lport, typically executing as NT AUTHORITY\\SYSTEM per README/notes. Notable operational details: exploit is ‘blind’ (no direct command output via HTTP); success is inferred by reverse-shell connection. Requires external payload generation with ysoserial.net and supports gadget selection (TypeConfuseDelegate default; alternatives TextFormattingRunProperties, ObjectDataProvider) and endpoint selection (TimerServiceAPI.rem vs TimerServiceEvents.rem).
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.