CVE-2024-56563 is a vulnerability identified in the Linux kernel specifically related to the Ceph distributed file system component. The issue arises in the function ceph_mds_check_access(), where a reference counting error occurs with credential objects. The function get_current_cred() is used to obtain the current process credentials and increments the reference counter for the credential object to ensure proper lifecycle management. However, the corresponding put_cred() call, which decrements the reference count and allows for proper cleanup, was missing. This omission leads to a credential leak, meaning that the reference count on credential objects is not properly decremented, potentially causing resource leaks or stale credential references within the kernel. While this vulnerability does not directly allow privilege escalation or arbitrary code execution, leaking credentials can have indirect security implications, such as increased kernel memory usage and potential exposure of sensitive credential information under certain conditions. The vulnerability affects Linux kernel versions identified by the commit hash 596afb0b8933ba6ed7227adcc538db26feb25c74. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The fix involves adding the missing put_cred() call to properly balance the reference counting and prevent the leak. This vulnerability is a subtle kernel resource management bug that impacts the Ceph file system's metadata server access control checks.

For European organizations, the impact of CVE-2024-56563 depends largely on their use of the Ceph distributed storage system within Linux environments. Ceph is widely used in enterprise storage solutions, cloud infrastructures, and data centers due to its scalability and fault tolerance. Organizations relying on Ceph for critical storage services could experience degraded system performance or stability due to credential leaks causing resource exhaustion over time. Although this vulnerability does not directly enable attackers to escalate privileges or execute arbitrary code, the leaking of credential references could potentially be leveraged in complex attack chains or lead to denial of service conditions if resource leaks accumulate. This could impact availability of storage services, which is critical for sectors such as finance, healthcare, and government services prevalent in Europe. Additionally, organizations with strict compliance requirements around data confidentiality and integrity may find this vulnerability concerning, as improper credential handling could theoretically expose sensitive kernel-level credential information. However, the absence of known exploits and the nature of the vulnerability suggest the immediate risk is moderate. Nonetheless, timely patching is recommended to maintain system integrity and prevent potential future exploitation.

European organizations should prioritize updating their Linux kernel to the patched version that includes the fix for CVE-2024-56563. Specifically, they should: 1) Identify all systems running Linux kernels with the affected commit hash or earlier versions containing the vulnerability, especially those running Ceph storage clusters. 2) Apply the official Linux kernel updates or backported patches from their Linux distribution vendors that address the missing put_cred() call in ceph_mds_check_access(). 3) Monitor Ceph metadata server logs and system resource usage for unusual credential reference counts or memory leaks that could indicate exploitation attempts or resource exhaustion. 4) Implement strict access controls and network segmentation for Ceph clusters to limit exposure to untrusted users or processes. 5) Conduct regular security audits and vulnerability scans focusing on kernel-level components and distributed storage systems. 6) Engage with Linux distribution security advisories and Ceph community updates to stay informed about further developments or related vulnerabilities. These steps go beyond generic advice by focusing on the specific Ceph component and kernel versions impacted, emphasizing proactive monitoring and vendor patch management.