{"api_version":"1","generated_at":"2026-09-21T20:31:10+00:00","cve":"CVE-2026-89986","urls":{"html":"https://cve.report/CVE-2026-89986","api":"https://cve.report/api/cve/CVE-2026-89986.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89986","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89986"},"summary":{"title":"mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()\n\nsyzbot reported a sleeping function called from invalid context splat in\nbucket_table_alloc().\n\nWhen rhashtable_insert_slow() rehashes the table under rcu_read_lock(), it\ncalls bucket_table_alloc(..., GFP_ATOMIC | __GFP_NOWARN).  If the bucket\ntable allocation uses vmalloc, __vmalloc_node_range_noprof() invokes\nvm_area_alloc_pages() -> alloc_pages_bulk_mempolicy_noprof() with the\npassed GFP_ATOMIC flags.\n\nIf the current task has an MPOL_WEIGHTED_INTERLEAVE mempolicy,\nalloc_pages_bulk_weighted_interleave() is called and currently hardcodes\nGFP_KERNEL when allocating the temporary weights array, triggering a\nmight_alloc() splat in atomic/RCU contexts.\n\nPass the gfp flags (masked with GFP_RECLAIM_MASK to strip page-allocator\nzone modifiers like __GFP_HIGHMEM) received by\nalloc_pages_bulk_weighted_interleave() to kmalloc() instead of hardcoding\nGFP_KERNEL.  Since the weights buffer is immediately initialized in full,\nkmalloc() is sufficient.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-16 11:17:09","updated_at":"2026-09-16 15:18:22"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/bcb3d0c867ee40dc48e9c085bf328fbc679b6656","name":"https://git.kernel.org/stable/c/bcb3d0c867ee40dc48e9c085bf328fbc679b6656","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/540e583b66d6402bf556fde5e53c817a54c1afe5","name":"https://git.kernel.org/stable/c/540e583b66d6402bf556fde5e53c817a54c1afe5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0ceda28f371df9e0bbdaa29214f71fe8298f23d8","name":"https://git.kernel.org/stable/c/0ceda28f371df9e0bbdaa29214f71fe8298f23d8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2943f1f4b7f2816177060eb9f551f2e6d8b629ba","name":"https://git.kernel.org/stable/c/2943f1f4b7f2816177060eb9f551f2e6d8b629ba","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89986","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89986","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fa3bea4e1f8202d787709b7e3654eb0a99aed758 bcb3d0c867ee40dc48e9c085bf328fbc679b6656 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fa3bea4e1f8202d787709b7e3654eb0a99aed758 0ceda28f371df9e0bbdaa29214f71fe8298f23d8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fa3bea4e1f8202d787709b7e3654eb0a99aed758 2943f1f4b7f2816177060eb9f551f2e6d8b629ba git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fa3bea4e1f8202d787709b7e3654eb0a99aed758 540e583b66d6402bf556fde5e53c817a54c1afe5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/mempolicy.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"bcb3d0c867ee40dc48e9c085bf328fbc679b6656","status":"affected","version":"fa3bea4e1f8202d787709b7e3654eb0a99aed758","versionType":"git"},{"lessThan":"0ceda28f371df9e0bbdaa29214f71fe8298f23d8","status":"affected","version":"fa3bea4e1f8202d787709b7e3654eb0a99aed758","versionType":"git"},{"lessThan":"2943f1f4b7f2816177060eb9f551f2e6d8b629ba","status":"affected","version":"fa3bea4e1f8202d787709b7e3654eb0a99aed758","versionType":"git"},{"lessThan":"540e583b66d6402bf556fde5e53c817a54c1afe5","status":"affected","version":"fa3bea4e1f8202d787709b7e3654eb0a99aed758","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/mempolicy.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.9"},{"lessThan":"6.9","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.110","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.51","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.110","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.51","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.5","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc2","versionStartIncluding":"6.9","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()\n\nsyzbot reported a sleeping function called from invalid context splat in\nbucket_table_alloc().\n\nWhen rhashtable_insert_slow() rehashes the table under rcu_read_lock(), it\ncalls bucket_table_alloc(..., GFP_ATOMIC | __GFP_NOWARN).  If the bucket\ntable allocation uses vmalloc, __vmalloc_node_range_noprof() invokes\nvm_area_alloc_pages() -> alloc_pages_bulk_mempolicy_noprof() with the\npassed GFP_ATOMIC flags.\n\nIf the current task has an MPOL_WEIGHTED_INTERLEAVE mempolicy,\nalloc_pages_bulk_weighted_interleave() is called and currently hardcodes\nGFP_KERNEL when allocating the temporary weights array, triggering a\nmight_alloc() splat in atomic/RCU contexts.\n\nPass the gfp flags (masked with GFP_RECLAIM_MASK to strip page-allocator\nzone modifiers like __GFP_HIGHMEM) received by\nalloc_pages_bulk_weighted_interleave() to kmalloc() instead of hardcoding\nGFP_KERNEL.  Since the weights buffer is immediately initialized in full,\nkmalloc() is sufficient."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - Triggering requires set_mempolicy(MPOL_WEIGHTED_INTERLEAVE) on the attacker's task and a local syscall that grows an rhashtable until GFP_ATOMIC kvmalloc falls back to vmalloc (nftables hash sets, tc flower, BPF rhashtable maps); softirq/packet paths use default_policy via in_interrupt() and cannot apply the attacker's mempolicy.\nAC:L - The attacker fully controls setup: set_mempolicy on their own task, insert enough rhashtable elements for a >PAGE_SIZE bucket table, and apply memory pressure so GFP_ATOMIC kmalloc fails and kvmalloc uses vmalloc; CONFIG_NUMA is standard on x86_64/arm64 distro and cloud kernels, and no attacker-uncontrollable race is required.\nPR:L - set_mempolicy() has no capability check, and the rhashtable rehash path is reachable by an unprivileged user via nftables or tc in a user+net namespace where CAP_NET_ADMIN is namespace-local; init-namespace root is not required.\nUI:N - The attacker sets their own mempolicy and drives the rhashtable inserts themselves; no victim action such as mounting a filesystem or opening a file is required.\nS:U - The illegal GFP_KERNEL allocation and any resulting RCU use-after-free of the rhashtable bucket table stay inside the host kernel's memory-management authority; this is standard in-kernel impact, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - Sleeping under rcu_read_lock() in rhashtable_insert_slow() on non-PREEMPT_RCU kernels can let the grace period complete and free the old bucket table before rhashtable_rehash_attach() uses it, yielding a use-after-free read of kernel heap.\nI:H - The same RCU-break UAF lets rhashtable_rehash_attach() cmpxchg old_tbl->future_tbl on a freed table, which is an attacker-sprayable kernel write primitive via heap reuse rather than a clean failure.\nA:H - GFP_KERNEL under rcu_read_lock produces a sleeping-from-invalid-context BUG/WARN (panic with panic_on_warn), can RCU-stall or deadlock if reclaim actually sleeps, and the bucket-table UAF can oops the kernel."}]}],"providerMetadata":{"dateUpdated":"2026-09-16T14:41:02.502Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bcb3d0c867ee40dc48e9c085bf328fbc679b6656"},{"url":"https://git.kernel.org/stable/c/0ceda28f371df9e0bbdaa29214f71fe8298f23d8"},{"url":"https://git.kernel.org/stable/c/2943f1f4b7f2816177060eb9f551f2e6d8b629ba"},{"url":"https://git.kernel.org/stable/c/540e583b66d6402bf556fde5e53c817a54c1afe5"}],"title":"mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89986","datePublished":"2026-09-16T10:33:01.545Z","dateReserved":"2026-09-11T19:38:34.779Z","dateUpdated":"2026-09-16T14:41:02.502Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-16 11:17:09","lastModifiedDate":"2026-09-16 15:18:22","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89986","Ordinal":"1","Title":"mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weight","CVE":"CVE-2026-89986","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89986","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()\n\nsyzbot reported a sleeping function called from invalid context splat in\nbucket_table_alloc().\n\nWhen rhashtable_insert_slow() rehashes the table under rcu_read_lock(), it\ncalls bucket_table_alloc(..., GFP_ATOMIC | __GFP_NOWARN).  If the bucket\ntable allocation uses vmalloc, __vmalloc_node_range_noprof() invokes\nvm_area_alloc_pages() -> alloc_pages_bulk_mempolicy_noprof() with the\npassed GFP_ATOMIC flags.\n\nIf the current task has an MPOL_WEIGHTED_INTERLEAVE mempolicy,\nalloc_pages_bulk_weighted_interleave() is called and currently hardcodes\nGFP_KERNEL when allocating the temporary weights array, triggering a\nmight_alloc() splat in atomic/RCU contexts.\n\nPass the gfp flags (masked with GFP_RECLAIM_MASK to strip page-allocator\nzone modifiers like __GFP_HIGHMEM) received by\nalloc_pages_bulk_weighted_interleave() to kmalloc() instead of hardcoding\nGFP_KERNEL.  Since the weights buffer is immediately initialized in full,\nkmalloc() is sufficient.","Type":"Description","Title":"mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weight"}]}}}