Medium [CVE-2026-74600] skip special zero mappings
This medium-severity Red Hat Linux advisory covers CVE-2026-74600 affecting Red Hat Enterprise Linux 10, Red Hat package: kernel.
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Summary
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(). 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.
A flaw was found in the Linux kernel's memory management, specifically within the `page_table_check` functionality. An unprivileged local attacker could exploit this by populating a sufficient number of zero mappings.
This action could lead to an overflow in the `file_map_count`, triggering a kernel panic and resulting in a Denial of Service (DoS) for the system. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-190. Affected Red Hat products: Red Hat Enterprise Linux 10.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 47 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 47 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 47 minutes ago·verify at source
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