CVE-2026-64292

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References