CVE-2026-53393

A flaw was found in the Linux kernel's Network File System (NFS) daemon. This vulnerability occurs when the NFS daemon fails to reset the write verifier during deferred writeback errors for UNSTABLE writes. A remote attacker, acting as an NFS client, could exploit this by performing operations that trigger these errors. This could lead to silent data loss, as clients might incorrectly assume their data has been durably written, violating the NFS durability contract.

This flaw is rated with Moderate severity for Red Hat Enterprise Linux because exploitation requires specific backend storage deferred writeback failures during unstable write operations, resulting in silent data inconsistency rather than privilege escalation or remote system compromise. The issue is restricted in scope to systems explicitly configured to act as NFS servers, a service that is not enabled by default on standard Red Hat Enterprise Linux installations. Systems operating solely as NFS clients or not exporting filesystems over NFS are unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.