A memory leak vulnerability in the Linux kernel NFS implementation allows remote attackers to induce a denial of service condition by pinning system resources.

The vulnerability exists in the nfsd_cross_mnt function, which fails to release path references when an error occurs during follow_down operations. An authenticated NFS client can trigger this flaw repeatedly to inflate dentry and mount counts, eventually leading to system instability or service failure.

Successful exploitation of this vulnerability leads to a denial of service, potentially rendering NFS services unavailable to legitimate users. Given the CVSS score of 7.5, this high-severity flaw poses a significant risk to operational continuity for environments relying on Linux-based file sharing. The inability to unmount filesystems or reclaim memory can necessitate a system reboot to restore functionality.

Immediate Action: Apply the vendor-provided kernel updates to version 6.6.157, 6.12.109, 6.18.50, or later, as applicable to your distribution.

Proactive Monitoring: Monitor system logs for recurring NFS-related errors and track memory usage or dentry cache growth on servers acting as NFS hosts.

Compensating Controls: Restrict access to NFS services to trusted IP addresses using firewall rules to minimize the exposure of the vulnerable nfsd interface.

Public Exploit Available: No (exploit_available: false)

The risk of service disruption warrants prioritized patching for all systems that function as NFS servers. Administrators should verify their kernel version and apply the appropriate security updates provided by their distribution maintainers to ensure that path references are correctly managed, thereby preventing memory exhaustion and potential system denial of service.