CVE-2026-64291 iommufd: Set veventq_depth upper bound

What is CVE-2026-64291?

CVE-2026-64291 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

iommufd: Set veventq_depth upper bound

iommufd_veventq_alloc() accepts any !0 veventq_depth from userspace, with an upper bound at U32_MAX.

This leaves a vulnerability where userspace can allocate excessively large queues to exhaust kernel memory reserves.

Cap the veventq_depth (maximum number of entries) to 1 << 19, matching the maximum number of entries in the SMMUv3 EVTQ (the largest use case today).

Which versions are affected by CVE-2026-64291?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64291?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-64291 being exploited?

There is no known exploitation of CVE-2026-64291 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64291, DEBIAN-CVE-2026-64291, GHSA-6gx3-fvx8-mx4p, ROOT-OS-UBUNTU-2204-CVE-2026-64291, UBUNTU-CVE-2026-64291.