# CVE-2026-100844: MONAI OS command injection in nnUNetV2Runner

Source: https://junglewise.ai/threats/cve-2026-100844-monai-before-1-6-0-is-vulnerable-to-os-command-injection-in-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-27. Updated: 2026-09-27  
License: CC BY 4.0 with a link back

CVE-2026-100844 · Severity: high · CVSS 8.4 · Published 2026-09-27

MONAI is a deep learning framework used for medical image analysis and training neural network models. A vulnerability in its nnUNetV2Runner component allows attackers to execute arbitrary operating system commands by injecting shell metacharacters into configuration files or command-line arguments. An attacker who tricks a user into loading a malicious YAML configuration file can gain full control of the system with the privileges of the user running the training job.

Technologies: [Project-MONAI MONAI](https://junglewise.ai/threats/technologies/project-monai-monai), [monai (PyPI)](https://junglewise.ai/threats/technologies/monai). Vendors: [Project-MONAI](https://junglewise.ai/threats/vendors/project-monai), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-100844 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100844 being exploited in the wild.

**How severe is CVE-2026-100844?** High severity, with a CVSS score of 8.4, published 27 September 2026.

**Which products and versions are affected?** Project-MONAI MONAI before 1.6.0; monai (PyPI) ECOSYSTEM:introduced=0,fixed=1.6.0.

**Is there a fix for CVE-2026-100844?** Yes. monai (PyPI): upgrade to 1.6.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-100844 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-100844?** Check whether you run Project-MONAI MONAI or monai (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- monai (PyPI): upgrade to 1.6.0 or later

  ```sh
  pip install "monai>=1.6.0"
  ```


## Technical details

OS command injection in nnUNetV2Runner via unsanitized user input (dataset_name_or_id from YAML config or CLI/kwargs arguments) concatenated into shell commands and executed with subprocess shell=True. Attack vector is local; user must load a crafted YAML configuration file and invoke training/validation functions (e.g., train_single_model()). No privileges or network access required; arbitrary code execution with user privileges.

## Affected products

- Project-MONAI MONAI before 1.6.0

## Identifiers

- CVE-2026-100844
- GHSA-rghg-q7wp-9767
- PYSEC-2026-4019

## Timeline

- 2026-09-27: disclosed
- 2026-06-11: patched: Version 1.6.0 released with patch

## References

- [https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-rghg-q7wp-9767](https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-rghg-q7wp-9767)
- [https://www.vulncheck.com/advisories/monai-before-1.6.0-os-command-injection-via-dataset-name-or-id](https://www.vulncheck.com/advisories/monai-before-1.6.0-os-command-injection-via-dataset-name-or-id)

## Related threats

- [MONAI MONAILabel server crash and inference corruption via crafted DICOM](https://junglewise.ai/threats/cve-2026-48705-monailabel-server-crash-and-silent-inference-corruption-via)
- [MONAI Auto3DSeg remote code execution via algo_from_json](https://junglewise.ai/threats/cve-2026-119578-monai-from-1-6-0-before-1-6-1-contains-a-remote-code-execution)
- [MONAI check_hash insufficient integrity verification](https://junglewise.ai/threats/cve-2026-118684-monai-before-1-6-1-contains-an-insufficient-integrity)
- [MONAI ConfigWorkflow remote code execution in logging.conf](https://junglewise.ai/threats/cve-2026-118683-monai-from-1-2-0-before-1-6-1-contains-a-remote-code-execution)
- [MONAI nnUNetV2Runner insecure deserialization in postprocessing](https://junglewise.ai/threats/cve-2026-109361-monai-1-2-0-before-1-6-1-contains-an-insecure-deserialization)