CVE-2025-12194 is a medium severity vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) affecting Legion of the Bouncy Castle Inc.'s Bouncy Castle for Java FIPS and LTS cryptographic libraries. The vulnerability arises from excessive memory allocation in multiple native cryptographic engine and digest implementations, including AES modes (CFB, GCM, CBC, CTR, CCM, GCMSIV) and SHA digests (SHA-256, SHA-224, SHA-3, SHA-512, SHA-384, SHAKE). These components are implemented in Java files targeting JDK 1.9 and are part of the core cryptographic processing pipeline. The flaw allows an attacker with local access to trigger excessive resource allocation, potentially leading to denial of service by exhausting memory or CPU resources. The CVSS 4.0 vector indicates low attack vector (local), low attack complexity, no privileges required, no user interaction, and partial impact on availability due to high resource consumption. The vulnerability affects all API modules in the specified versions (FIPS 2.1.0 through 2.1.1 and LTS 2.73.0 through 2.73.7). No public exploits or patches are currently available, but the issue is published and should be addressed promptly. The vulnerability does not compromise cryptographic confidentiality or integrity but can disrupt services relying on these cryptographic operations, including secure communications, authentication, and data protection mechanisms.

For European organizations, the impact primarily involves potential denial of service conditions in applications and services that rely on the affected Bouncy Castle Java FIPS and LTS libraries for cryptographic functions. This can affect financial institutions, government agencies, healthcare providers, and critical infrastructure operators that use Java-based security modules for encryption, digital signatures, or secure communications. Excessive resource consumption can degrade system performance, cause application crashes, or lead to unavailability of security services, thereby impacting business continuity and compliance with data protection regulations such as GDPR. Since Bouncy Castle is widely used in open-source and commercial Java applications, the scope of affected systems can be broad, especially in sectors with heavy Java adoption. The lack of known exploits reduces immediate risk, but the vulnerability's presence in core cryptographic libraries necessitates urgent mitigation to prevent potential exploitation by insiders or malware with local access.

1. Monitor and audit resource usage of Java applications using Bouncy Castle libraries to detect abnormal memory or CPU consumption patterns. 2. Apply strict runtime limits on cryptographic operations, such as timeouts and memory caps, to prevent resource exhaustion. 3. Restrict local access to systems running vulnerable versions to trusted personnel only, minimizing the attack surface. 4. Stay informed about official patches or updates from Legion of the Bouncy Castle Inc. and plan timely upgrades to versions beyond 2.1.1 (FIPS) and 2.73.7 (LTS) once released. 5. Implement application-level input validation to limit the size and complexity of cryptographic requests that could trigger excessive allocation. 6. Use containerization or sandboxing to isolate cryptographic processes and limit the impact of resource exhaustion. 7. Conduct penetration testing and fuzzing focused on cryptographic API usage to identify potential exploitation vectors. 8. Review and harden access controls and logging to detect and respond to suspicious local activity that might exploit this vulnerability.