CVE-2026-46318
Received Received - Intake
Memory Leak in Linux Kernel HugeTLBFS

Publication date: 2026-06-09

Last updated on: 2026-06-09

Assigner: kernel.org

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.
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Meta Information
Published
2026-06-09
Last Modified
2026-06-09
Generated
2026-06-09
AI Q&A
2026-06-09
EPSS Evaluated
N/A
NVD
CVE-2026-46318
EUVD
EUVD-2026-35408
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability in the Linux kernel involves an incorrect handling of hugetlb VMA lock allocation during the mmap_prepare stage. Specifically, a failed allocation after mmap_prepare might cause the lock to leak. The issue arose from a patch that updated hugetlbfs to use mmap_prepare, which was later reverted to fix the problem.

The problem is related to memory management in the kernel, where the virtual memory area (VMA) lock could be improperly allocated and leaked if an error occurred during the mmap_prepare process.

Impact Analysis

The vulnerability could lead to a lock leak in the kernel's memory management subsystem. While the exact impact is not detailed, such leaks can potentially cause resource exhaustion or instability in the system, affecting performance or reliability.

However, the description notes that there is no risk of a merge causing similar issues due to specific flags set for hugetlb mappings, which may limit the scope of the impact.

Mitigation Strategies

The vulnerability was resolved by reverting a specific commit that incorrectly handled hugetlb VMA lock allocation at the mmap_prepare stage. Immediate mitigation involves applying the patch that reverts the problematic commit to correct the underlying issue.

Since this is a Linux kernel vulnerability related to hugetlbfs, updating your Linux kernel to a version that includes this revert patch is the recommended immediate step.

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