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.
MONAI through 1.6.0 _get_fake_spatial_shape eval() Sandbox Bypass via Attribute Chains
Problem type
Affected products
Project-MONAI
<= 1.6.0 - AFFECTED
References
https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-h89g-r5pc-wxfm
https://www.vulncheck.com/advisories/monai-through-1.6.0-get-fake-spatial-shape-eval-sandbox-bypass-via-attribute-chains
GitHub Security Advisories
GHSA-j335-cfj5-2fw8
MONAI through 1.6.0 contains an eval injection vulnerability in _get_fake_spatial_shape() in...
https://github.com/advisories/GHSA-j335-cfj5-2fw8MONAI 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.
https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-h89g-r5pc-wxfm
https://nvd.nist.gov/vuln/detail/CVE-2026-100842
https://www.vulncheck.com/advisories/monai-through-1.6.0-get-fake-spatial-shape-eval-sandbox-bypass-via-attribute-chains
https://github.com/advisories/GHSA-j335-cfj5-2fw8
JSON source
https://cveawg.mitre.org/api/cve/CVE-2026-100842Click to expand
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"dateUpdated": "2026-09-27T01:28:38.149Z",
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"datePublic": "2026-08-18T00:00:00.000Z",
"title": "MONAI through 1.6.0 _get_fake_spatial_shape eval() Sandbox Bypass via Attribute Chains",
"descriptions": [
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"value": "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."
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