Executive brief
@hulumi/policies is a library that validates AWS IAM policies against CIS Benchmark standards. Versions before 1.3.2 failed to properly inspect inline and attached IAM policies when enforcing administrator-policy guards, allowing policies with administrator-equivalent permissions to incorrectly pass validation checks. This could enable unauthorized users to gain elevated access through policies that should have been rejected.
Technical details
The vulnerability is a privilege management bypass (CWE-269) in @hulumi/policies, a policy validation library for AWS IAM. The validator component failed to fully inspect inline and attached IAM policy shapes when evaluating the CIS 1.16 administrator-policy guardrail, allowing admin-equivalent policies to pass validation checks. The attack requires no authentication or user interaction—an attacker can craft IAM policies that contain administrative permissions but are structured in ways the validator fails to detect, allowing these policies to be deployed. This permits attackers to gain unauthorized administrative access to AWS resources. The vulnerability was patched in version 1.3.2 with enhanced policy shape inspection and regression testing.
Affected products
- hulumi @hulumi/policies < 1.3.2
Timeline
- 2026-05-21: disclosed: Vulnerability published as GHSA-4xrh-5m3m-328w
- 2026-05-21: patched: Fix released in version 1.3.2