Medium [CVE-2026-74369] fix u-a-f in luo_file_unpreserve_files and luo_file_finish

In the Linux kernel, the following vulnerability has been resolved: liveupdate: fix u-a-f in luo_file_unpreserve_files() and luo_file_finish() In luo_file_unpreserve_files() and luo_file_finish(), reorder module_put() and xa_erase() to ensure the file handler module remains pinned while its operations are being accessed.

Specifically, luo_get_id() dereferences fh->ops->get_id, so the module reference must be held until after xa_erase() (which calls luo_get_id) completes. For luo_file_finish(), this requires moving the module_put() call out of the luo_file_finish_one() helper and into the main loop of luo_file_finish() itself.

This use-after-free vulnerability occurs due to an incorrect order of operations when managing file handler modules. Specifically, the system attempts to access module operations after the module's reference count has been decremented, leading to the use of freed memory.

A local attacker could exploit this to cause system instability or potentially execute arbitrary code. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-911. Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.