MONAI: Unsafe deserialization in NumpyReader allows arbitrary code execution via malicious .npy files

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.8 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary The NumpyReader class in monai/data/imagereader.py unconditionally uses np.load(name, allowpickle=True) (line 1276), enabling arbitrary code execution when loading a crafted .npy or .npz file. This affects all MONAI versions up to and including the latest commit (5b71547). The allowpickle parameter is hardcoded to True and cannot be overridden by the user (the docstring explicitly states kwargs are accepted "except allowpickle"). Details Vulnerable code (permalink): The NumpyReader is automatically selected by MONAI's LoadImage transform for any file with .npy or .npz extension (see monai/transforms/io/array.py line 68: "numpyreader": NumpyReader). This means the entire standard data pipeline (LoadImage, PersistentDataset, CacheDataset, SmartCacheDataset, etc.) is vulnerable. The allowpickle=True parameter enables Python's pickle protocol during numpy loading. Pickle is known to be unsafe for untrusted data, as it can execute arbitrary code during deserialization via the…

Published by the source

18 Aug 2026, 20:22 UTC

Last modified by the source

18 Aug 2026, 20:22 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wg9g-w2j2-8pgr

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-wg9g-w2j2-8pgr

Advisory: MONAI: Unsafe deserialization in NumpyReader allows arbitrary code execution via malicious .npy files
IDs: GHSA-wg9g-w2j2-8pgr
Record: https://patchnext.com/advisories/ghsa-wg9g-w2j2-8pgr (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: monai 1.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI monai: affected < 1.6.0; fixed in 1.6.0

## Suggested inspection (read-only)
- `python -m pip show monai`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on monai.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wg9g-w2j2-8pgr (GitHub-reviewed advisory GHSA-wg9g-w2j2-8pgr lists affected ranges: PyPI monai >=0 <1.6.0)

Commands are suggestions: review each one before running it.