Project-MONAI up to 1.5.1 _download_from_ngc_private path traversal

Summaryinfo

A vulnerability was found in Project-MONAI MONAI up to 1.5.1. It has been rated as critical. Affected by this issue is the function _download_from_ngc_private. Performing a manipulation results in path traversal. This vulnerability is identified as CVE-2026-21851. The attack can be initiated remotely. There is not any exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability classified as critical has been found in Project-MONAI MONAI up to 1.5.1. This affects the function _download_from_ngc_private. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on integrity, and availability. The summary by CVE is:

MONAI (Medical Open Network for AI) is an AI toolkit for health care imaging. In versions up to and including 1.5.1, a Path Traversal (Zip Slip) vulnerability exists in MONAI's `_download_from_ngc_private()` function. The function uses `zipfile.ZipFile.extractall()` without path validation, while other similar download functions in the same codebase properly use the existing `safe_extract_member()` function. Commit 4014c8475626f20f158921ae0cf98ed259ae4d59 fixes this issue.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-21851 since 01/05/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Applying the patch 4014c8475626f20f158921ae0cf98ed259ae4d59 is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-1039). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Project Management Software

Vendor

• Project-MONAI

Name

• MONAI

Version

• 1.5.0
• 1.5.1

License

• open-source

Website

• Product: https://github.com/Project-MONAI/MONAI/

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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