Project-MONAI up to 1.5.x nnUNetV2Runner nnunetv2_runner.py train_single_model dataset_name_or_id os command injection

Summaryinfo

A vulnerability marked as problematic has been reported in Project-MONAI MONAI up to 1.5.x. Affected by this issue is the function train_single_model of the file monai/apps/nnunet/nnunetv2_runner.py of the component nnUNetV2Runner. This manipulation of the argument dataset_name_or_id causes os command injection. This vulnerability is registered as CVE-2026-100844. The attack needs to be launched locally. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Project-MONAI MONAI up to 1.5.x. It has been declared as problematic. Affected by this vulnerability is the function train_single_model of the file monai/apps/nnunet/nnunetv2_runner.py of the component nnUNetV2Runner. The manipulation of the argument dataset_name_or_id with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-100844 since 09/27/2026. The exploitation appears to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1202 for this issue.

Upgrading to version 1.6.0 eliminates this vulnerability.

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Productinfo

Type

• Project Management Software

Vendor

• Project-MONAI

Name

• MONAI

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5

Website

• Product: https://github.com/Project-MONAI/MONAI/

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