CVE-2025-11621 is an authentication bypass vulnerability classified under CWE-288, affecting HashiCorp Vault's AWS Auth method. Vault uses the AWS Auth method to authenticate clients based on AWS IAM roles. The vulnerability occurs when the configured bound_principal_iam role is the same across multiple AWS accounts or when a wildcard is used, which can cause Vault to incorrectly validate the identity of an AWS principal. This misconfiguration allows an attacker with low privileges and network access to bypass authentication controls without user interaction, gaining unauthorized access to Vault secrets. The vulnerability affects Vault Community Edition versions prior to 1.21.0 and Enterprise versions 1.20.5, 1.19.11, and 1.16.27 and earlier. The CVSS v3.1 score is 8.1 (high), reflecting the network attack vector, low attack complexity, required privileges, no user interaction, and high impact on confidentiality and integrity. Although no known exploits are reported in the wild, the vulnerability poses a serious risk to organizations relying on Vault for secret management, especially in environments where AWS IAM roles are reused or overly permissive. The flaw can lead to unauthorized disclosure and modification of sensitive secrets, potentially compromising downstream systems and applications. HashiCorp has addressed this issue in the specified patched versions. Organizations must review their AWS Auth configurations, particularly the bound_principal_iam roles, to ensure they are unique and tightly scoped to prevent exploitation.

For European organizations, the impact of CVE-2025-11621 is significant due to the widespread adoption of HashiCorp Vault for managing secrets and credentials in cloud environments, especially AWS. Successful exploitation can lead to unauthorized access to sensitive credentials, API keys, and other secrets stored in Vault, which can cascade into broader compromise of critical infrastructure and data. This can affect confidentiality and integrity of data, disrupt business operations, and lead to regulatory non-compliance under GDPR due to potential data breaches. Organizations operating multi-account AWS environments or using shared IAM roles are at higher risk. The breach of Vault secrets can facilitate lateral movement, privilege escalation, and data exfiltration. Given the critical role of Vault in securing cloud-native applications and infrastructure, the vulnerability could undermine trust in security controls and lead to financial and reputational damage. The absence of known exploits in the wild provides a window for proactive mitigation but should not reduce urgency in patching and configuration review.

1. Immediately upgrade HashiCorp Vault to the fixed versions: Community Edition 1.21.0 or Enterprise versions 1.21.0, 1.20.5, 1.19.11, or 1.16.27 and later. 2. Audit and restrict the bound_principal_iam roles used in the AWS Auth method to ensure they are unique per AWS account and avoid using wildcards. 3. Implement strict IAM role scoping and least privilege principles to minimize the risk of role misuse. 4. Enable detailed logging and monitoring of Vault authentication attempts to detect anomalous or unauthorized access patterns. 5. Conduct regular security reviews of Vault configurations and AWS IAM policies to identify and remediate misconfigurations. 6. Consider network segmentation and access controls to limit exposure of Vault endpoints to trusted networks and clients only. 7. Educate DevOps and security teams about the risks of shared or wildcard IAM roles in multi-account AWS environments. 8. Integrate Vault access monitoring with SIEM solutions to enable rapid detection and response to suspicious activity. 9. Test incident response plans to handle potential Vault compromise scenarios effectively.