CVE-2025-12044 is a vulnerability classified under CWE-770 (Allocation of Resources Without Limits or Throttling) affecting HashiCorp Vault, a widely used secrets management tool. The vulnerability stems from a regression introduced after a previous fix (HCSEC-2025-24) intended to mitigate denial of service attacks via complex JSON payloads. Specifically, Vault processes JSON payloads before applying rate limiting, allowing an unauthenticated attacker to send maliciously crafted JSON data that triggers excessive resource consumption. This can exhaust system resources such as CPU and memory, leading to denial of service conditions where Vault becomes unresponsive or crashes. The vulnerability affects Vault Community Edition version 1.20.3 and certain Enterprise versions prior to 1.21.0. The CVSS v3.1 base score is 7.5, reflecting high severity due to network attack vector, no required privileges or user interaction, and a direct impact on availability. No known exploits are currently reported in the wild, but the ease of exploitation and critical role of Vault in securing secrets make this a significant risk. The vulnerability does not compromise confidentiality or integrity but can disrupt operations dependent on Vault for secret management. HashiCorp has released patches in Vault Community Edition 1.21.0 and Enterprise versions 1.16.27, 1.19.11, 1.20.5, and 1.21.0 to address this issue.

For European organizations, the primary impact of CVE-2025-12044 is the potential for denial of service against Vault servers, which are critical components in modern DevOps and cloud infrastructure environments. Disruption of Vault services can halt automated secret retrieval, impacting application deployments, CI/CD pipelines, and secure access to sensitive credentials. This can lead to operational downtime, delayed business processes, and increased risk of manual errors in secret handling. Organizations relying heavily on Vault for compliance and security controls may face regulatory scrutiny if service outages affect data protection measures. The unauthenticated nature of the attack increases the risk of exploitation by external threat actors, including opportunistic attackers and advanced persistent threats targeting European enterprises. Given Vault’s widespread use in financial services, technology, and government sectors across Europe, the availability impact could be significant, especially in countries with high cloud adoption and critical infrastructure reliance on Vault.

1. Immediately upgrade all affected Vault instances to the patched versions: Vault Community Edition 1.21.0 or Enterprise versions 1.16.27, 1.19.11, 1.20.5, or 1.21.0. 2. Implement network-level access controls to restrict unauthenticated access to Vault endpoints, such as IP whitelisting, VPNs, or zero trust network segmentation. 3. Deploy Web Application Firewalls (WAFs) or API gateways capable of detecting and rate-limiting suspicious JSON payloads to prevent abuse before reaching Vault. 4. Monitor Vault server resource utilization and logs for unusual spikes in JSON processing or request rates indicative of exploitation attempts. 5. Conduct regular security assessments and penetration testing focused on API abuse and resource exhaustion scenarios. 6. Educate DevOps and security teams about this vulnerability and ensure incident response plans include steps for Vault service disruptions. 7. Consider implementing additional rate limiting or request throttling mechanisms at the application or infrastructure level to complement Vault’s internal controls.