CVE-2026-53394: In the Linux kernel, the following vulnerability has been resolved: nfsd: avoid leaking pre-allocated openowner on unco

A memory leak vulnerability exists in the Linux kernel's NFSv4.0 (a network file sharing protocol) implementation where pre-allocated memory is not properly freed when certain race conditions occur (situations where two processes compete for the same resource at the same time). The bug happens when multiple concurrent OPEN requests with the same owner name are processed, and one thread encounters an unconfirmed owner while another thread is simultaneously modifying the shared data structure, causing the kernel to overwrite a pointer to previously allocated memory without freeing it first.