{"id":"CVE-2026-74600","summary":"mm/page_table_check: skip special zero mappings","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_table_check: skip special zero mappings\n\npage_table_check_set() and page_table_check_clear() account mappings based\non PageAnon().  Shared zero-page PTEs and huge zero PMDs are special\nmappings, but page_table_check can still account them as file-backed\npages.\n\nAn unprivileged process can populate enough zero mappings to overflow\nfile_map_count and hit the existing BUG_ON().  The PTE path can do this\nwith the shared zero page, and the PMD path can do the same with huge zero\nmappings.\n\nSkip special zero mappings in the user page-table accounting paths.  Keep\nthe PTE-side pte_special() check, and identify huge zero PMDs from the\nmapped folio instead of pmd_special().  That covers architectures where\npmd_special() is a no-op without adding huge_zero_pfn checks to the\ngeneric counter helpers.","modified":"2026-08-25T03:51:37.541989812Z","published":"2026-08-22T15:31:49.334Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74600.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/7755be923e325dc300f4b0c3e1ad7e91b28b3cb9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8db4bab826ccc9ec10fa41736a48031cd338d392"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74600.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74600"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"df4e817b710809425d899340dbfa8504a3ca4ba5"},{"fixed":"7755be923e325dc300f4b0c3e1ad7e91b28b3cb9"},{"fixed":"b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc"},{"fixed":"8db4bab826ccc9ec10fa41736a48031cd338d392"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74600.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.17.0"},{"fixed":"6.18.46"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74600.json"}}],"schema_version":"1.9.0"}