CVE-2026-53381

A flaw was found in the virtiofs component of the Linux kernel. A use-after-free (UAF) vulnerability exists during submount unmount operations. This occurs because the iput() function, called from fuse_release_end(), can attempt to access a super block that has already been destroyed. This can lead to a kernel panic, resulting in a denial of service.

This vulnerability is rated as Moderate severity because exploitation requires local access, high attack complexity to trigger a race condition during filesystem teardown, and primarily threatens system availability rather than arbitrary code execution. The flaw specifically affects virtualized environments where virtio-fs filesystems with submounts are actively mounted and torn down, which is not an active default setup in standard deployments. An unprivileged local user able to trigger asynchronous file releases during an unmount sequence could induce a kernel panic, resulting in a denial of service.

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.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.