CVE-2023-53083 is a vulnerability identified in the Linux kernel's NFS daemon (nfsd) splice read implementation. The issue arises in the function nfsd_splice_actor, which is responsible for placing pages containing file data into the svc_rqst->rq_pages array during splice read operations. The vulnerability occurs when a splice read returns a partial page at the end, such as when the underlying filesystem provides a short read that does not fill the entire page. In this scenario, nfsd_splice_actor inserts the partial page into the rq_pages array and returns. On subsequent calls, the remainder of the page may be filled and the function attempts to add the same page again into the array, leading to duplicate entries. This duplication corrupts the reply data structure. If repeated multiple times, the rq_next_page index can overrun the array bounds, corrupting adjacent memory fields including rq_respages and rq_next_page pointers themselves. This memory corruption can lead to unpredictable behavior, including potential denial of service or arbitrary code execution depending on exploitation. The root cause was a removed check in a prior commit (91e23b1c3982) that originally prevented adding the same page twice during splice continuation. The fix involves restoring the check to avoid inserting a page multiple times. This vulnerability affects specific Linux kernel versions identified by commit hashes and was published on May 2, 2025. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a significant risk particularly to environments running Linux servers with NFS services enabled. NFS is widely used in enterprise and cloud infrastructures for file sharing and storage. Exploitation could lead to memory corruption in the kernel space, potentially causing system crashes (denial of service) or enabling privilege escalation or arbitrary code execution if an attacker can craft malicious NFS requests. This could disrupt critical business operations, compromise sensitive data confidentiality and integrity, and impact availability of shared resources. Organizations relying on Linux-based NFS servers for file storage, virtualization, or container orchestration are especially at risk. Given the kernel-level nature of the flaw, successful exploitation could undermine system security controls and lead to broader network compromise. The lack of known exploits currently provides a window for proactive patching before active attacks emerge.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2023-53083 as soon as it becomes available. Until patches are applied, administrators should consider disabling or restricting NFS services where feasible, especially on systems exposed to untrusted networks. Network segmentation and strict firewall rules should limit access to NFS ports (typically TCP/UDP 2049) to trusted hosts only. Monitoring NFS server logs for unusual splice read activity or memory corruption symptoms can provide early detection. Additionally, organizations should implement kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and enable security modules like SELinux or AppArmor to reduce exploitation impact. Regular backups and incident response plans should be reviewed to prepare for potential exploitation scenarios. Finally, tracking Linux kernel mailing lists and vendor advisories will ensure timely awareness of patch releases and exploit developments.