CVE-2025-6037 is a security vulnerability identified in HashiCorp Vault, specifically affecting the TLS certificate authentication method. Vault and Vault Enterprise versions prior to the fixed releases (Community Edition 1.20.1 and Enterprise 1.20.1, 1.19.7, 1.18.12, and 1.16.23) improperly validate client certificates when configured with a non-CA (Certificate Authority) certificate as a trusted certificate. This misconfiguration flaw falls under CWE-295, which relates to improper certificate validation. The vulnerability allows an attacker to craft a malicious client certificate that could be accepted by Vault as valid, enabling the attacker to impersonate another user. This impersonation could lead to unauthorized access to secrets and sensitive data managed by Vault. The CVSS v3.1 base score is 6.8, indicating a medium severity level. The vector details (AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H) show that the attack can be performed remotely over the network with low attack complexity but requires high privileges and user interaction. The vulnerability impacts confidentiality, integrity, and availability, as an attacker could gain unauthorized access, modify data, or disrupt services. No known exploits are currently reported in the wild, but the vulnerability is publicly disclosed and patched. The root cause is the acceptance of client certificates that are not properly validated against a trusted CA, which violates the security assumptions of TLS client authentication in Vault's certificate auth method.

For European organizations using HashiCorp Vault, this vulnerability poses a significant risk to the confidentiality and integrity of sensitive secrets, credentials, and cryptographic keys managed by Vault. Since Vault is widely used for secret management, identity brokering, and encryption key lifecycle management, exploitation could lead to unauthorized access to critical infrastructure components, cloud environments, and internal applications. This could result in data breaches, lateral movement within networks, and disruption of business operations. The requirement for high privileges and user interaction somewhat limits the attack surface; however, insider threats or compromised privileged users could exploit this flaw to escalate access or impersonate other users. Given the increasing adoption of Vault in European financial, governmental, and technology sectors, the impact could be substantial if not mitigated promptly. Additionally, regulatory compliance frameworks such as GDPR impose strict requirements on protecting sensitive data, and exploitation of this vulnerability could lead to regulatory penalties and reputational damage.

European organizations should immediately upgrade affected Vault instances to the patched versions: Vault Community Edition 1.20.1 or Vault Enterprise 1.20.1, 1.19.7, 1.18.12, or 1.16.23. Until upgrades are applied, organizations should audit their Vault TLS certificate authentication configurations to ensure that only proper CA certificates are used as trusted certificates, avoiding non-CA certificates in this role. Implement strict certificate issuance policies and monitor certificate usage logs for anomalies. Employ multi-factor authentication and restrict privileged user access to reduce the risk of insider exploitation. Additionally, conduct regular security assessments and penetration testing focused on Vault authentication mechanisms. Network segmentation and monitoring of Vault API access can help detect and contain potential misuse. Finally, maintain an incident response plan tailored to secrets management compromise scenarios.