---
id: CVE-2026-100842
title: >-
  MONAI through 1.6.0 contains an eval injection vulnerability in
  _get_fake_spatial_shape() in monai/bundle/scripts.py
summary: >-
  MONAI through 1.6.0 contains an eval injection vulnerability in
  _get_fake_spatial_shape() in monai/bundle/scripts.py. The function validates
  shape expressions with a helper that walks the AST and only collects ast.Name
  nodes, rejecting a…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-95
vendor: project-monai
product: monai
affected:
  - monai <= 1.6.0
published: '2026-09-27'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T17:49:34.937'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100842'
references:
  - url: >-
      https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-h89g-r5pc-wxfm
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/monai-through-1.6.0-get-fake-spatial-shape-eval-sandbox-bypass-via-attribute-chains
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-h89g-r5pc-wxfm
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
  - osv
  - pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-30T16:54:04.586486Z'
epss: 0.00183
epssPercentile: 0.0785
ingestedAt: '2026-09-27T02:41:45.573Z'
aliases:
  - PYSEC-2026-4017
  - GHSA-h89g-r5pc-wxfm
ecosystem: pip
patched:
  - monai 1.6.1rc0
scores:
  nvd: 7
  osv: 8.8
---

## Overview

MONAI through 1.6.0 contains an eval injection vulnerability in _get_fake_spatial_shape() in monai/bundle/scripts.py. The function validates shape expressions with a helper that walks the AST and only collects ast.Name nodes, rejecting any name other than 'p' or 'n', before passing the string to eval(). Expressions built solely from constants and attribute, subscript, or call nodes (for example "(1).__class__.__bases__[0].__subclasses__()" or "int.__class__.__init__.__globals__") contain no ast.Name nodes and therefore bypass the allowlist. Because the shape value originates from bundle metadata consumed by _get_real_input_data and verify_net_in_out (reachable through the bundle 'verify_net_in_out' CLI flow), an attacker who can influence a bundle's metadata can escape the eval sandbox via object introspection chains and achieve code execution in this non-default flow.

## Affected

- `monai <= 1.6.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-100842)

Affected packages:

- `monai < 1.6.1rc0`

Patched in:

- `monai 1.6.1rc0`

Source: https://osv.dev/vulnerability/PYSEC-2026-4017