Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-25T00:00:00 kernel: iommufd: Move vevent memory allocation outside spinlock 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-770

In the Linux kernel, the following vulnerability has been resolved: iommufd: Move vevent memory allocation outside spinlock The veventq memory allocation happens inside the spinlock. Given its depth is decided by the user space, this leaves a vulnerability, where userspace can allocate large queues to exhaust atomic memory reserves. Move the allocation outside the spinlock and use GFP_NOWAIT, which can fail fast under memory pressure without dipping into the GFP_ATOMIC reserves or direct-reclaiming from the threaded IRQ handler. On allocation failure, queue the lost_events_header (so userspace learns of the drop) and return -ENOMEM so the caller learns of the kernel-side memory pressure. This is intentionally distinct from the queue-overflow path, which also queues the lost_events_header but returns 0: a full queue is an expected userspace-pacing condition rather than a kernel error. A subsequent change will cap the upper bound of the veventq_depth.

A flaw was found in the Linux kernel's iommufd component. A local user can exploit this vulnerability by allocating large `veventq` queues, which are processed inside a spinlock. This can lead to the exhaustion of atomic memory reserves, resulting in a Denial of Service (DoS) condition.

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64292 https://nvd.nist.gov/vuln/detail/CVE-2026-64292 https://lore.kernel.org/linux-cve-announce/2026072504-CVE-2026-64292-322d@gregkh/T