CVE-2026-100844 MONAI before 1.6.0 OS Command Injection via dataset_name_or_id

High 8.6 Published 27 Sep 2026 Updated 8 Oct 2026

Attackers can execute arbitrary OS commands by crafting a malicious YAML configuration file processed by the MONAI nnUNetV2Runner component.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-100844?

CVE-2026-100844 is a high-severity command injection vulnerability in Project-MONAI MONAI, published on 27 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-78

Which versions are affected by CVE-2026-100844?

3 open source packages ship an affected version, including monai and MONAI. It affects 1 product.

Package	Affected	Fixed in
`monai` PyPI	All versions	`1.6.0`
`monai` PyPI	All versions	`1.6.0`
`MONAI` PyPI	All versions	`1.6.0`

Products include Project-Monai Monai.

How do I fix CVE-2026-100844?

Upgrade monai to 1.6.0 or later.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2026-100844 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100844 exists.

Sources

Also known as GHSA-rghg-q7wp-9767, GHSA-x7wh-49x3-6748, PYSEC-2026-4019.