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CVE-2026-74600

Unknown

Last modified

CVE-2026-74600 is a vulnerability of currently unknown severity. 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().

Description

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= df4e817b710809425d899340dbfa8504a3ca4ba5, < 7755be923e325dc300f4b0c3e1ad7e91b28b3cb9; >= df4e817b710809425d899340dbfa8504a3ca4ba5, < b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc; >= df4e817b710809425d899340dbfa8504a3ca4ba5, < 8db4bab826ccc9ec10fa41736a48031cd338d392
LinuxLinux5.17

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74600?
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.
How severe is CVE-2026-74600?
Severity scoring for CVE-2026-74600 is pending analysis.
How do I fix CVE-2026-74600?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST