CVE-2026-82856 in Hulumi
Summary
by MITRE • 08/31/2026
@hulumi/policies versions before 1.3.2 fail to properly validate set-qualified AWS IAM condition operators in GitHub OIDC trust policies. Attackers can use ForAnyValue:StringLike operators to hide wildcard GitHub Actions OIDC subject conditions from security guardrails.
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Analysis
by VulDB Data Team • 08/31/2026
The vulnerability identified in @hulumi/policies prior to version 1.3.2 represents a critical flaw in the logic used to validate AWS Identity and Access Management (IAM) condition operators within OpenID Connect trust policies for GitHub Actions. This issue specifically targets the handling of set-qualified string comparison operators, most notably ForAnyValue:StringLike. In standard IAM policy evaluation, these operators are designed to check if any value in a multi-valued context matches a specified pattern. However, the validation logic implemented in earlier versions of this library fails to correctly interpret or restrict the usage of such operators when applied to GitHub Actions OIDC subject conditions. This oversight allows for the construction of policies that appear compliant with security guardrails but effectively bypass them through logical manipulation of how wildcard characters are processed within these specific conditional contexts.
From a technical perspective, the core flaw lies in the insufficient sanitization and validation of policy statements before they are applied to AWS resources. When an attacker utilizes ForAnyValue:StringLike operators, they can craft conditions that match a broad range of inputs while technically satisfying the syntactic requirements expected by security tools or automated compliance checks. Specifically, this allows for the concealment of wildcard patterns in GitHub Actions OIDC subject claims. By leveraging the set-based evaluation nature of these operators, an adversary can ensure that their malicious actions fall within the allowed scope defined by a seemingly restrictive policy. This effectively neutralizes the intended protective measures designed to limit access based on specific repository or workflow identifiers, creating a gap where unauthorized code execution or privilege escalation becomes possible without triggering standard alerting mechanisms.
The operational impact of this vulnerability is severe for organizations relying on automated CI/CD pipelines secured via GitHub OIDC federation. If an attacker can inject malicious workflows or compromise a trusted pipeline due to these overly permissive conditions, they may gain access to sensitive infrastructure resources, secrets, and deployment environments managed by AWS. This could lead to data exfiltration, lateral movement within the cloud environment, or complete system compromise depending on the permissions granted under the affected policy. The ability to hide wildcard conditions means that security teams might believe their IAM policies are tightly scoped when they are actually exposing critical assets to a much wider attack surface than intended.
This vulnerability aligns with CWE-284 Improper Access Control and CWE-798 Use of Hard-coded Credentials if the OIDC configuration itself is manipulated, but primarily it reflects CWE-693 Protection Mechanism Failure where the security control fails to enforce its intended restriction. In terms of MITRE ATT&CK framework, this relates to T1098 Exploitation of Cloud Infrastructure Remote Services and potentially T1528 Steal Application Access Token if OIDC tokens are misused due to weak policy enforcement. The exploitation vector involves manipulating the trust relationship between GitHub Actions and AWS IAM services through malformed or ambiguously interpreted condition keys.
To mitigate this risk, organizations must immediately upgrade @hulumi/policies to version 1.3.2 or later where these validation logic errors have been corrected. It is also advisable to review existing IAM policies that utilize ForAnyValue operators with StringLike conditions for GitHub OIDC trusts and ensure they are strictly scoped to specific repository IDs and workflow paths rather than relying on broad pattern matching. Implementing least-privilege principles by restricting the scope of assumed roles further reduces the blast radius in case of future vulnerabilities. Regular auditing of IAM policies using tools that understand the nuances of set-based condition operators will help maintain robust security postures against such logical bypasses.