CVE-2026-100844
project-monai monai
Summary
MONAI before 1.6.0 is vulnerable to OS command injection in the nnUNetV2Runner component (monai.apps.nnunet.nnunetv2_runner). User-controlled values taken from the YAML configuration file (notably dataset_name_or_id) and from CLI/kwargs arguments are concatenated into a command string without quoting or validation and then passed to subprocess with shell=True, so shell metacharacters (e.g., ';' on Linux, '&' on Windows) are interpreted. If a victim loads and processes a crafted configuration file — for example by instantiating nnUNetV2Runner with the malicious YAML and invoking a training/validation job such as train_single_model() — arbitrary commands are executed with the privileges of the user running the job.
Published 2026-09-27 · first seen here 2026-10-10
Analysis & write-ups
No technical write-up from a research team yet. Contact Zero checks Unit 42, Google/Mandiant, Microsoft, Talos, CrowdStrike, Rapid7, watchTowr and others several times a day, plus NVD and CISA reference links.
Where it shows in your logs
Server or web application · Command or code injection (remote code execution) medium confidence
What to look for
- Shell metacharacters or encoded payloads in request parameters (; | ` $( %0a)
- The vulnerable process spawning shells, then downloaders (curl, wget, certutil, Invoke-WebRequest)
- The application's process (w3wp.exe, java, tomcat, node, php-fpm, httpd, python) starting shells or LOLBins (cmd, powershell, sh, bash, curl, wget, certutil)
- New script files in web roots (.jsp, .aspx, .php): a web shell
- Requests to unusual URLs on the application from internet IPs right before any of the above
- Outbound connections from the server to new external IPs
Data sources
Web server and WAF logs · ATT&CK DS0015 Application Log Content
- Sentinel
W3CIISLogAppServiceHTTPLogsAzureDiagnostics (Application Gateway / Front Door WAF)_Im_WebSession- Splunk
Web.Webms:iis:autoaccess_combinedWAF / proxy sourcetypes- CrowdStrike
Falcon Next-Gen SIEM: third-party web / WAF / proxy logs
Process creation · ATT&CK DS0009 Process Creation
- Sentinel
DeviceProcessEventsSecurityEvent (4688)Sysmon Event ID 1_Im_ProcessCreate- Splunk
Endpoint.ProcessesXmlWinEventLog:Microsoft-Windows-Sysmon/OperationalWinEventLog:Security (4688)- CrowdStrike
ProcessRollup2SyntheticProcessRollup2
File creation · ATT&CK DS0022 File Creation
- Sentinel
DeviceFileEventsSysmon Event ID 11_Im_FileEvent- Splunk
Endpoint.FilesystemSysmon Event ID 11- CrowdStrike
NewExecutableWrittenNewScriptWritten*FileWritten events
Network connections · ATT&CK DS0029 Network Connection Creation / Network Traffic Flow
- Sentinel
DeviceNetworkEventsCommonSecurityLog (firewall)_Im_NetworkSession- Splunk
Network_Traffic.All_TrafficFirewall sourcetypes (pan:traffic, fortigate_traffic, cisco:asa)- CrowdStrike
NetworkConnectIP4NetworkReceiveAcceptIP4NetworkConnectIP6
A generic baseline worked out from the product type and weakness (CWE-78), not a detection. Check table and field names against your environment. Hunt queries for Sigma, Splunk, Sentinel and CrowdStrike are coming.