CVE-2026-98729
Received Received - Intake

x86/mm: Fix hugetlb mapping alignment issue on AMD F15h

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h get_align_mask() returns huge_page_mask_align() for hugetlbfs, but get_align_bits() adds va_align.bits regardless, so vm_unmapped_area() returns an address off the huge page boundary and __unmap_hugepage_range() hits BUG_ON(start & ~huge_page_mask(h)) at teardown. This can be triggered on Carrizo and FX-8370E, both hstates. Pass the file to get_align_bits() and skip the randomisation for hugetlbfs. [ bp: Massage commit message. ]

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98729
EUVD
EUVD-2026-103814

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
Linux Linux 1317a5e7f7b1336eac4097f0ef4f5cd7ae72f1d0
Linux Linux 1317a5e7f7b1336eac4097f0ef4f5cd7ae72f1d0
Linux Linux 1317a5e7f7b1336eac4097f0ef4f5cd7ae72f1d0
Linux Linux 6.13

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability affects the Linux kernel's memory management on AMD F15h processors. It involves a misalignment issue where hugetlb mappings (large memory pages) are incorrectly handled during address allocation. The kernel's get_align_mask() and get_align_bits() functions interact poorly, causing vm_unmapped_area() to return an address not aligned to huge page boundaries. This triggers a BUG_ON assertion failure in __unmap_hugepage_range() during teardown, potentially crashing the system.

Detection Guidance

This vulnerability is specific to the Linux kernel's memory management on AMD F15h processors with hugetlbfs. Detection requires checking kernel logs for hugetlbfs-related BUG_ON crashes or examining kernel version and processor compatibility.

Impact Analysis

This vulnerability can cause system crashes or instability when using hugetlbfs on affected AMD processors (Carrizo and FX-8370E). It may lead to unexpected kernel errors during memory operations involving large pages, disrupting services relying on these memory allocations.

Mitigation Strategies

Apply the latest Linux kernel update that resolves this issue. If using AMD F15h processors with hugetlbfs, avoid using huge pages until patched. Monitor kernel logs for hugetlbfs-related errors.

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