EUVD-2026-80594
GHSA-f5rq-g72v-q29m
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local unprivileged user can set the mempolicy (AV:L/PR:L), but the atomic RCU vmalloc-rehash trigger is timing-dependent (AC:H); impact is a splat/instability only (A:L, C:N/I:N).
Primary rating from Vendor (Linux).
CVSS VectorVendor: Linux
Lifecycle Timeline
6DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()
syzbot reported a sleeping function called from invalid context splat in bucket_table_alloc().
When rhashtable_insert_slow() rehashes the table under rcu_read_lock(), it calls bucket_table_alloc(..., GFP_ATOMIC | __GFP_NOWARN). If the bucket table allocation uses vmalloc, __vmalloc_node_range_noprof() invokes vm_area_alloc_pages() -> alloc_pages_bulk_mempolicy_noprof() with the passed GFP_ATOMIC flags.
If the current task has an MPOL_WEIGHTED_INTERLEAVE mempolicy, alloc_pages_bulk_weighted_interleave() is called and currently hardcodes GFP_KERNEL when allocating the temporary weights array, triggering a might_alloc() splat in atomic/RCU contexts.
Pass the gfp flags (masked with GFP_RECLAIM_MASK to strip page-allocator zone modifiers like __GFP_HIGHMEM) received by alloc_pages_bulk_weighted_interleave() to kmalloc() instead of hardcoding GFP_KERNEL. Since the weights buffer is immediately initialized in full, kmalloc() is sufficient.
AnalysisAI
A context-inappropriate allocation in the Linux kernel's weighted-interleave memory policy path causes a sleeping (GFP_KERNEL) allocation to be performed while executing in atomic/RCU context. The bug exists only in kernels that provide the MPOL_WEIGHTED_INTERLEAVE mempolicy, introduced in Linux 6.9, and is triggered when an authenticated local user has that policy set on the current task while an rhashtable bucket-table allocation rehashes under rcu_read_lock() with GFP_ATOMIC and falls back to vmalloc (__vmalloc_node_range_noprof → vm_area_alloc_pages → alloc_pages_bulk_mempolicy → alloc_pages_bulk_weighted_interleave), which then hardcodes GFP_KERNEL for its temporary weights array. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires local code execution able to set an MPOL_WEIGHTED_INTERLEAVE mempolicy on the current task (introduced in 6.9), AND a code path where a bucket-table allocation via rhashtable_insert_slow() rehashes under rcu_read_lock() with GFP_ATOMIC and falls back to vmalloc (__vmalloc_node_range_noprof → vm_area_alloc_pages → alloc_pages_bulk_mempolicy). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a low-real-risk defect despite the vendor's 7.8 HIGH rating. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply the vendor patch by upgrading to Linux 6.12.110, 6.18.51, 7.2.5 or 7.3-rc2 (or a later release containing the corresponding stable-branch commit: bcb3d0c867ee40dc48e9c085bf328fbc679b6656, 0ceda28f371df9e0bbdaa29214f71fe8298f23d8, 2943f1f4b7f2816177060eb9f551f2e6d8b629ba or 540e583b66d6402bf556fde5e53c817a54c1afe5, see https://git.kernel.org/stable/c/bcb3d0c867ee40dc48e9c085bf328fbc679b6656 and the EUVD entry https://nvd.nist.gov/vuln/detail/CVE-2026-89986); vendor-released patches are available, so no long-term compensating controls should be needed. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory every Linux host and container base image to identify systems running kernel 6.9 or later, confirming whether the MPOL_WEIGHTED_INTERLEAVE mempolicy is compiled in and whether CONFIG_DEBUG_ATOMIC_SLEEP is enabled in staging or production builds, and flag any server where local users have memory-policy privileges (set_mempolicy/mbind) that could enable the weighted-interleave path. …
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