CVE-2024-53173 is a high-severity use-after-free vulnerability identified in the Linux kernel's implementation of NFSv4.0 (Network File System version 4.0). The flaw arises in the asynchronous open() operation when two threads attempt to open files concurrently and are forced to abort before receiving a reply. Specifically, the vulnerability occurs due to improper handling of the rpc_task pointers during the abort sequence. When one thread aborts, the call to nfs_release_seqid() in the function nfs4_opendata_free() can mistakenly reference and free the rpc_task pointer of the other thread, leading to a use-after-free condition. This memory corruption flaw can be exploited to cause arbitrary code execution, denial of service, or data corruption, as it impacts confidentiality, integrity, and availability. The root cause is a race condition in the management of sequence IDs and RPC tasks during asynchronous file open operations. The fix involves ensuring that if the RPC call is aborted before nfs_wait_on_sequence() completes, nfs_release_seqid() is called in nfs4_open_release() before freeing the rpc_task, preventing the use-after-free scenario. The vulnerability is tracked under CWE-416 (Use After Free) and has a CVSS v3.1 score of 7.8, indicating high severity. No known exploits are reported in the wild as of the publication date, but the nature of the flaw and its impact make it a critical patch for Linux systems using NFSv4.0.

For European organizations, this vulnerability poses significant risks, especially for enterprises and public sector entities relying on Linux servers with NFSv4.0 for file sharing and storage across distributed systems. Exploitation could lead to unauthorized access to sensitive data, disruption of critical services, or system crashes, affecting business continuity and data integrity. Given the widespread use of Linux in European data centers, cloud infrastructures, and government systems, the vulnerability could be leveraged to compromise confidential information or disrupt operations. The requirement for local privileges (PR:L) and no user interaction (UI:N) means that attackers with limited access could escalate privileges or cause denial of service. This is particularly concerning for multi-tenant environments and organizations with complex networked storage setups. The vulnerability's impact on confidentiality, integrity, and availability makes it a high-priority issue for European organizations to address promptly to maintain compliance with data protection regulations such as GDPR and to safeguard critical infrastructure.

European organizations should implement the following specific mitigations: 1) Immediately apply the official Linux kernel patches that address CVE-2024-53173 once available, ensuring all affected systems are updated. 2) Audit and monitor NFSv4.0 usage within the environment to identify systems that utilize asynchronous open() operations and prioritize patching those hosts. 3) Restrict local user privileges to the minimum necessary to reduce the risk of exploitation by unprivileged users. 4) Implement runtime protections such as kernel memory protection mechanisms (e.g., KASLR, SMEP, SMAP) to mitigate exploitation impact. 5) Employ network segmentation and access controls to limit exposure of NFS servers to only trusted hosts and networks. 6) Monitor system logs and kernel messages for anomalies related to NFS operations or crashes that could indicate exploitation attempts. 7) Consider temporary workarounds such as disabling asynchronous open() operations if feasible until patches are applied. 8) Incorporate this vulnerability into vulnerability management and incident response plans to ensure rapid detection and remediation.