{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80718","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.788Z","datePublished":"2026-08-28T06:53:15.490Z","dateUpdated":"2026-08-29T06:22:34.556Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:22:34.556Z"},"descriptions":[{"lang":"en","value":"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->populated, whose size is pcpu_unit_pages, bitmap. \nSince bit N in chunk->populated means page offset N inside every unit is\nbacked.  When nr_units > 1, the function writes beyond chunk->populated. \nFix it by using chunk->nr_pages.\n\nIt also fixes the global pcpu_nr_empty_pop_pages accounting, since\npcpu_balance_free() only iterates up to chunk->nr_pages.\n\nCommit a63d4ac4ab609 (\"percpu: make percpu-km set chunk->populated bitmap\nproperly\") introduced the bitmap overflow issue.  Later, commit\nb539b87fed37f (\"percpu: implmeent pcpu_nr_empty_pop_pages and\nchunk->nr_populated\") added pcpu_nr_empty_pop_pages and caused the\naccounting issue."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - pcpu_create_chunk() is reached only when the kernel dynamic percpu allocator creates a new chunk via pcpu_alloc_noprof() or pcpu_balance_populated(); both require local syscalls driving __alloc_percpu() exhaustion, and percpu-km applies only on NOMMU/UP kernels with no remote packet path into this code.\nAC:L - On affected SMP NOMMU builds where nr_units>1, an attacker can deterministically force pcpu_create_chunk() by spraying percpu-consuming allocations (e.g., repeated socket() or BPF percpu map creation) until existing chunks are full; no race or victim state outside attacker control is needed.\nPR:L - Dynamic percpu allocation is reachable with basic local user access; unprivileged attackers can obtain effective capability via user namespaces (unshare -Urn) plus CAP_NET_RAW-class socket paths or CAP_BPF where enabled, matching percpu-spray patterns in similar allocator CVEs.\nUI:N - The attacker drives percpu exhaustion and new-chunk creation entirely from its own processes via repeated local syscalls; no victim mount, file open, or administrator interaction is required.\nS:U - The bitmap overflow corrupts kernel kmalloc slab objects and percpu bookkeeping within the same kernel security domain; this is standard kernel heap corruption, not a VM, IOMMU, or sandbox boundary escape.\nC:H - bitmap_set() writes up to (nr_units*pcpu_unit_pages) bits into chunk->populated[] sized for only pcpu_unit_pages, overflowing the kzalloc allocation in pcpu_alloc_chunk() and exposing or corrupting adjacent kernel heap memory.\nI:H - The same out-of-bounds write corrupts neighboring slab objects and inflates nr_populated/nr_empty_pop_pages accounting, providing attacker-influenced heap metadata corruption exploitable for arbitrary kernel writes and privilege escalation.\nA:H - Slab overflow during chunk initialization can immediately oops or panic the kernel and leaves corrupted allocator state that causes subsequent percpu operations to fault, consistent with rubric guidance for heap corruption bugs."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/percpu-km.c"],"versions":[{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"5f43d2c1bea280dcdfabaf156c25e7402fb8039f","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"92c43ac3c2b09eb16162e8144e73c00b7c3e29d6","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"6fc7da2a052f2825fff785e860e67183f5acaaba","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"01504da375f5b19df195cb1cb1cf1dd184318f97","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"a6940b84c8c035da465b7165fdfcfb005545724e","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"32134cf9211b83bed9076d0739c5906fbea4c763","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"5c7fc39bf19abb38a996aaad77b3e3a8f48581c3","status":"affected","versionType":"git"},{"version":"a63d4ac4ab6094c051a5a240260d16117a7a2f86","lessThan":"89b1b79c308818a715e75f28744b70d8940a07c9","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/percpu-km.c"],"versions":[{"version":"3.18","status":"affected"},{"version":"0","lessThan":"3.18","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.183","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.151","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.103","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.44","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.8","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/5f43d2c1bea280dcdfabaf156c25e7402fb8039f"},{"url":"https://git.kernel.org/stable/c/92c43ac3c2b09eb16162e8144e73c00b7c3e29d6"},{"url":"https://git.kernel.org/stable/c/6fc7da2a052f2825fff785e860e67183f5acaaba"},{"url":"https://git.kernel.org/stable/c/01504da375f5b19df195cb1cb1cf1dd184318f97"},{"url":"https://git.kernel.org/stable/c/a6940b84c8c035da465b7165fdfcfb005545724e"},{"url":"https://git.kernel.org/stable/c/32134cf9211b83bed9076d0739c5906fbea4c763"},{"url":"https://git.kernel.org/stable/c/5c7fc39bf19abb38a996aaad77b3e3a8f48581c3"},{"url":"https://git.kernel.org/stable/c/89b1b79c308818a715e75f28744b70d8940a07c9"}],"title":"mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()","x_generator":{"engine":"bippy-1.2.0"}}}}