# CVE-2026-100840: MONAI remote code execution in bundle configuration engine

Source: https://junglewise.ai/threats/cve-2026-100840-monai-through-1-6-0-contains-a-remote-code-execution  
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-2026-100840 · Severity: high · CVSS 7.8 · Published 2026-09-27

MONAI is a deep learning framework for medical imaging used to load and execute pre-trained model bundles. The bundle configuration engine allows arbitrary Python code execution through two mechanisms: unvalidated _target_ values resolved to any importable function, and $ expressions passed directly to eval(). An attacker can publish a malicious bundle that executes arbitrary code when a victim loads it using monai.bundle.load() or monai.bundle.run().

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-2026-100840 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100840 being exploited in the wild.

**How severe is CVE-2026-100840?** High severity, with a CVSS score of 7.8, published 27 September 2026.

**Which products and versions are affected?** Project-MONAI MONAI through 1.6.0; monai (PyPI) ECOSYSTEM:introduced=0,fixed=1.6.1rc0.

**Is there a fix for CVE-2026-100840?** Yes. monai (PyPI): upgrade to 1.6.1rc0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-100840 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-100840?** 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 1.6.1rc0 or later

  ```sh
  pip install "monai>=1.6.1rc0"
  ```


## Technical details

The vulnerability exists in MONAI's configuration parser, which resolves _target_ values via locate() without an allowlist and passes $ expressions to eval() without sanitization. These sinks are reachable from monai.bundle.load() (which downloads bundles and parses configs) and monai.bundle.run(), triggered when the network definition is instantiated. Exploitation requires user interaction (loading a bundle) but grants full code execution in the loading process; no patches are available as of the advisory date.

## Affected products

- Project-MONAI MONAI through 1.6.0

## Identifiers

- CVE-2026-100840
- GHSA-873f-pvrv-4x83
- PYSEC-2026-4015

## Timeline

- 2026-08-21: disclosed
- 2026-09-27: advisory

## References

- [https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-873f-pvrv-4x83](https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-873f-pvrv-4x83)
- [https://www.vulncheck.com/advisories/monai-through-1.6.0-remote-code-execution-via-bundle-configuration](https://www.vulncheck.com/advisories/monai-through-1.6.0-remote-code-execution-via-bundle-configuration)

## 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)