CVE-2026-74311

A flaw was found in the Linux kernel. During a system restore operation, the virtio real-time clock (RTC) component fails to properly manage virtual queues (virtqueues). If the reinitialization of these virtqueues fails, the system attempts to delete queues using incorrect memory references. This can lead to a null pointer dereference, causing the guest kernel to crash and resulting in a denial of service.

A moderate severity denial-of-service flaw was found in the Linux kernel virtio RTC (real-time clock) driver. During a guest device restore operation, viortc_restore() reinitializes the device's virtqueues without first deleting the old virtqueues that viortc_freeze() intentionally left in place so that the alarm queue could still wake the system. If virtqueue reinitialization fails on the virtio-pci transport, the transport error path can run vp_del_vqs() against a newly allocated vp_dev->vqs array while vdev->vqs still references the old virtqueues, resulting in a NULL pointer dereference in vp_del_vq() and a crash of the guest kernel. Triggering the flaw requires local privileged access inside the guest or control over the guest lifecycle operations that perform the device restore. The impact is limited to the availability of the guest: there is no effect on the host and no confidentiality or integrity impact. Red Hat Product Security therefore rates this flaw Moderate (CVSS 3.1 score 5.5, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), which differs from the upstream CVEORG score of 7.8 because the upstream vector also assumes high confidentiality and integrity impact, while this NULL pointer dereference only causes a denial of service. All currently listed Red Hat product streams, including the Red Hat Enterprise Linux and Red Hat In-Vehicle OS kernel, kernel-rt, and kernel-ivos-qualcomm components, are marked not affected because the vulnerable code is not present in the shipped kernels.

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.