CVE-2026-63800

A flaw was found in the Linux kernel's parallel Network File System (pNFS) component. An issue in the pnfs_update_layout() function causes a use-after-free vulnerability due to incorrect ordering of memory management operations. This flaw can be triggered when the system attempts to update a pNFS layout, potentially leading to system instability, crashes, or a denial of service. In some scenarios, this type of memory corruption could be exploited by a local attacker to achieve arbitrary code execution.

Red Hat rates this vulnerability as Moderate because exploitation requires an active NFSv4 mount with parallel NFS (pNFS) enabled, limiting exposure to systems configured with pNFS storage. Triggering the use-after-free condition depends on specific layout return timing during layout recovery. Although memory corruption could theoretically lead to local privilege escalation or a kernel crash causing denial of service, the high execution complexity and specific network filesystem prerequisites reduce the risk.

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.