{"id":"CVE-2026-80718","summary":"mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()\n\nIn pcpu_create_chunk(), nr_pages is the total contiguous backing\nallocation, i.e., nr_units * pcpu_unit_pages, but pcpu_chunk_populated()\nuses it to set chunk-\u003epopulated, whose size is pcpu_unit_pages, bitmap. \nSince bit N in chunk-\u003epopulated means page offset N inside every unit is\nbacked.  When nr_units \u003e 1, the function writes beyond chunk-\u003epopulated. \nFix it by using chunk-\u003enr_pages.\n\nIt also fixes the global pcpu_nr_empty_pop_pages accounting, since\npcpu_balance_free() only iterates up to chunk-\u003enr_pages.\n\nCommit a63d4ac4ab609 (\"percpu: make percpu-km set chunk-\u003epopulated bitmap\nproperly\") introduced the bitmap overflow issue.  Later, commit\nb539b87fed37f (\"percpu: implmeent pcpu_nr_empty_pop_pages and\nchunk-\u003enr_populated\") added pcpu_nr_empty_pop_pages and caused the\naccounting issue.","modified":"2026-08-29T03:47:17.285032775Z","published":"2026-08-28T06:53:15.490Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80718.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/01504da375f5b19df195cb1cb1cf1dd184318f97"},{"type":"WEB","url":"https://git.kernel.org/stable/c/32134cf9211b83bed9076d0739c5906fbea4c763"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5c7fc39bf19abb38a996aaad77b3e3a8f48581c3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5f43d2c1bea280dcdfabaf156c25e7402fb8039f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6fc7da2a052f2825fff785e860e67183f5acaaba"},{"type":"WEB","url":"https://git.kernel.org/stable/c/89b1b79c308818a715e75f28744b70d8940a07c9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/92c43ac3c2b09eb16162e8144e73c00b7c3e29d6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a6940b84c8c035da465b7165fdfcfb005545724e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80718.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80718"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a63d4ac4ab6094c051a5a240260d16117a7a2f86"},{"fixed":"5f43d2c1bea280dcdfabaf156c25e7402fb8039f"},{"fixed":"92c43ac3c2b09eb16162e8144e73c00b7c3e29d6"},{"fixed":"6fc7da2a052f2825fff785e860e67183f5acaaba"},{"fixed":"01504da375f5b19df195cb1cb1cf1dd184318f97"},{"fixed":"a6940b84c8c035da465b7165fdfcfb005545724e"},{"fixed":"32134cf9211b83bed9076d0739c5906fbea4c763"},{"fixed":"5c7fc39bf19abb38a996aaad77b3e3a8f48581c3"},{"fixed":"89b1b79c308818a715e75f28744b70d8940a07c9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80718.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.18.0"},{"fixed":"5.10.265"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.216"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.183"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.151"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.103"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.44"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80718.json"}}],"schema_version":"1.9.0"}