CVE-2025-6037 is a vulnerability identified in HashiCorp Vault, specifically in its TLS certificate authentication method. The issue arises when Vault is configured to use a non-CA (Certificate Authority) certificate as a trusted certificate for client authentication. Under this configuration, Vault fails to properly validate client certificates, which violates the expected certificate validation process (CWE-295: Improper Certificate Validation). This improper validation allows an attacker to craft a malicious client certificate that could impersonate another legitimate user. The vulnerability affects multiple versions of Vault, including Vault Community Edition 1.20.0 and earlier, and Vault Enterprise versions prior to 1.20.1, 1.19.7, 1.18.12, and 1.16.23, where the issue has been fixed. The CVSS v3.1 base score is 6.8, indicating a medium severity level. The vector string (AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H) indicates that the attack can be performed remotely over the network with low complexity but requires high privileges and user interaction, and it impacts confidentiality, integrity, and availability significantly. Although no known exploits are reported in the wild yet, the vulnerability poses a serious risk because Vault is widely used for secrets management and protecting sensitive credentials in enterprise environments. Exploiting this flaw could allow attackers to bypass authentication controls, gain unauthorized access to secrets, and potentially escalate privileges within an organization’s infrastructure.

For European organizations, the impact of this vulnerability can be substantial. Many enterprises and public sector entities in Europe rely on HashiCorp Vault to securely manage secrets, API keys, tokens, and certificates critical to their infrastructure and applications. Successful exploitation could lead to unauthorized access to sensitive data, including personal data protected under GDPR, intellectual property, and operational secrets. This could result in data breaches, regulatory fines, reputational damage, and operational disruptions. Given the medium CVSS score but high impact on confidentiality, integrity, and availability, attackers with sufficient privileges could impersonate users and escalate access, undermining trust in the security of the Vault environment. This is particularly critical for sectors such as finance, healthcare, and government agencies in Europe, where data protection and operational continuity are paramount.

To mitigate this vulnerability, European organizations should immediately upgrade to the patched versions of HashiCorp Vault: Community Edition 1.20.1 or Enterprise versions 1.20.1, 1.19.7, 1.18.12, or 1.16.23. Organizations should audit their Vault TLS certificate authentication configurations to ensure that only proper CA certificates are used as trusted certificates, avoiding configurations that rely on non-CA certificates. Additionally, implement strict certificate validation policies and monitor Vault logs for any unusual authentication attempts or anomalies. Employ network segmentation and access controls to limit who can interact with Vault’s authentication endpoints, reducing the risk of exploitation. Regularly review and rotate certificates and credentials stored in Vault to minimize exposure. Finally, integrate Vault usage with centralized security monitoring and incident response processes to quickly detect and respond to potential misuse.