Linux Kernel up to 7.1.8 Page Table Check mm/page_table_check.c page_table_check_set/page_table_check_clear resource consumption

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 7.1.8. This affects the function page_table_check_set/page_table_check_clear of the file mm/page_table_check.c of the component Page Table Check. The manipulation results in resource consumption. This vulnerability is known as CVE-2026-74600. Attacking locally is a requirement. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 7.1.8. Affected is the function page_table_check_set/page_table_check_clear of the file mm/page_table_check.c of the component Page Table Check. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/page_table_check: skip special zero mappings page_table_check_set() and page_table_check_clear() account mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings, but page_table_check can still account them as file-backed pages. An unprivileged process can populate enough zero mappings to overflow file_map_count and hit the existing BUG_ON(). The PTE path can do this with the shared zero page, and the PMD path can do the same with huge zero mappings. Skip special zero mappings in the user page-table accounting paths. Keep the PTE-side pte_special() check, and identify huge zero PMDs from the mapped folio instead of pmd_special(). That covers architectures where pmd_special() is a no-op without adding huge_zero_pfn checks to the generic counter helpers.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-74600 since 08/15/2026. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 7.1.9 eliminates this vulnerability. Applying the patch b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc/8db4bab826ccc9ec10fa41736a48031cd338d392 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.1.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

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