CVE-2026-97619

A flaw was found in the Linux kernel's io_uring subsystem. Improperly deferring write completion accounting to background task work can create a circular locking dependency when a filesystem freeze operation is performed. A local user could exploit this flaw by issuing asynchronous write operations while initiating a filesystem freeze, causing the kernel to deadlock and resulting in a Denial of Service (DoS).

A low impact flaw was found in the Linux kernel's io_uring subsystem. When an asynchronous io_uring write is in flight, the kernel defers dropping the superblock writers (SB_FREEZE_WRITE) read-side protection to task_work owned by the ring-owning task. If that task then blocks inside freeze_super() (for example via FS_IOC_SHUTDOWN or FIFREEZE, operations that require CAP_SYS_ADMIN) while waiting to acquire the same semaphore write-side, the deferred unlock can never run, creating a circular locking dependency. The affected tasks enter uninterruptible sleep and the system hangs, resulting in a local denial of service. There is no impact to confidentiality or integrity. In Red Hat's assessment this issue is rated low severity: exploitation requires local access, privileged filesystem freeze operations, and precise timing, and the result is a hang only. Affected products are Red Hat Enterprise Linux 9 and 10, Red Hat In-Vehicle OS 2, and OpenShift Container Platform releases built on RHEL 9 CoreOS (4.16 and later), whose kernels contain the introducing change. Earlier streams (RHEL 6, 7, and 8, RHEL 9.2, and OpenShift 4.12 through 4.15) are not affected because the vulnerable code is not present in those kernels. A fix is currently deferred for the affected streams; the residual risk is limited to a local denial of service by a privileged local actor able to time a filesystem freeze against in-flight io_uring writes.

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 do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.