CVE-2026-46318 Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare"

What is CVE-2026-46318?

CVE-2026-46318 is a medium-severity memory corruption vulnerability in Linux kernel, published on 9 Jun 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:

Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare"

This reverts commit ea52cb24cd3f ("mm/hugetlbfs: update hugetlbfs to use mmap_prepare") with conflict resolution to account for changes in commit ea52cb24cd3f ("mm/hugetlbfs: update hugetlbfs to use mmap_prepare").

The patch incorrectly handled hugetlb VMA lock allocation at the mmap_prepare stage, where a failed allocation occurring after mmap_prepare is called might result in the lock leaking.

There is no risk of a merge causing a similar issues, as VMA_DONTEXPAND_BIT is set for hugetlb mappings.

As a first step in addressing this issue, simply revert the change so we can rework how we do this having corrected the underlying issues.

We maintain the VMA flags changes as best we can, accounting for the fact that we were working with a VMA descriptor previously and propagating like-for-like changes for this.

Note that we invoke vma_set_flags() and do not call vma_start_write() as vm_flags_set() does. This is OK as it's being done in an .mmap hook where the VMA is not yet linked into the tree so nobody else can be accessing it.

Which versions are affected by CVE-2026-46318?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-46318?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-46318 being exploited?

There is no known exploitation of CVE-2026-46318 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 DEBIAN-CVE-2026-46318, GHSA-rq5m-62rx-j536, UBUNTU-CVE-2026-46318.