CVE-2026-93172: mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplug

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplug We miss a failed allocation check for pgdat->per_cpu_nodestats, which results in a NULL deref when we offset into the per-cpu area. Propagate -ENOMEM up the stack and leave per_cpu_nodestats pointing at boot_nodestats so a later online can retry the allocation. hotadd_init_pgdat() returns NULL on failure, which __try_online_node() already maps to -ENOMEM. On failure nothing needs to be unwound: - the node is never marked online - per_cpu_nodestats is left pointing at boot_nodestats - __add_memory_resource() cleans up pending memblock resources - later online attempts retry the per_cpu_nodestats allocation

Affected products

Linux: 4.8 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

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