CVE-2026-64292: iommufd: Move vevent memory allocation outside spinlock

Vulnerability summary

CVE-2026-64292 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.1% of scored vulnerabilities.

Timeline

1. 25-07-2026
   PublishedVulnerability first disclosed.
2. 17-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-401Missing Release of Memory after Effective LifetimeThe product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.