{"id":"CVE-2026-74384","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-74384","generatedAt":"2026-10-28T02:19:11.255Z","title":"In the Linux kernel, the following vulnerability has been resolved: nvme-multipath: fix flex array size in struct nvme_ns_head struct nvme_ns_head contains a flexible array member, current_path[], which is indexed using the NUMA node ID:…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme-multipath: fix flex array size in struct nvme_ns_head\n\nstruct nvme_ns_head contains a flexible array member, current_path[],\nwhich is indexed using the NUMA node ID:\nhead->current_path[numa_node_id()]\n\nThe structure is currently allocated as:\nsize = sizeof(struct nvme_ns_head) +\n       (num_possible_nodes() * sizeof(struct nvme_ns *));\nhead = kzalloc(size, GFP_KERNEL);\n\nThis allocation assumes that NUMA node IDs are sequential and densely\npacked from 0 .. num_possible_nodes() - 1. While this assumption holds\non many systems, it is not always true on some architectures such as\npowerpc.\n\nOn some powerpc systems, NUMA node IDs can be sparse. For example:\nNUMA:\n  NUMA node(s):              6\n  NUMA node0 CPU(s):         80-159\n  NUMA node8 CPU(s):         0-79\n  NUMA node252 CPU(s):\n  NUMA node253 CPU(s):\n  NUMA node254 CPU(s):\n  NUMA node255 CPU(s):\n\nThat is, the possible/online NUMA node IDs are: 0, 8, 252, 253, 254, 255\nIn this case: num_possible_nodes() = 6\n\nSo memory is allocated for only 6 entries in current_path[]. However,\nthe array is later indexed using the actual NUMA node ID. As a result,\naccesses such as:\nhead->current_path[8] or\nhead->current_path[252]\ngoes out of bounds, leading to the following KASAN splat:\n\n==================================================================\nBUG: KASAN: slab-out-of-bounds in nvme_mpath_revalidate_paths+0x22c/0x290 [nvme_core]\nWrite of size 8 at addr c00020003bda35b8 by task kworker/u641:2/1997\n\nCPU: 1 UID: 0 PID: 1997 Comm: kworker/u641:2 Not tainted 7.1.0-rc5-dirty #14 PREEMPT(lazy)\nHardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV\nWorkqueue: async async_run_entry_fn\nCall Trace:\n[c000200037fa7510] [c0000000021c23d4] dump_stack_lvl+0x88/0xdc (unreliable)\n[c000200037fa7540] [c0000000009fda90] print_report+0x22c/0x67c\n[c000200037fa7630] [c0000000009fd508] kasan_report+0x108/0x220\n[c000200037fa7740] [c0000000009fff48] __asan_store8+0xe8/0x120\n[c000200037fa7760] [c008000018e76474] nvme_mpath_revalidate_paths+0x22c/0x290 [nvme_core]\n[c000200037fa7800] [c008000018e6556c] nvme_update_ns_info+0x4a4/0x5e0 [nvme_core]\n[c000200037fa7a50] [c008000018e66270] nvme_alloc_ns+0x6d8/0x1a70 [nvme_core]\n[c000200037fa7c20] [c008000018e679fc] nvme_scan_ns+0x3f4/0x630 [nvme_core]\n[c000200037fa7d10] [c00000000031f22c] async_run_entry_fn+0x9c/0x3a0\n[c000200037fa7db0] [c0000000002fa544] process_one_work+0x414/0xa10\n[c000200037fa7ec0] [c0000000002fbf00] worker_thread+0x320/0x640\n[c000200037fa7f80] [c00000000030d0f8] kthread+0x278/0x290\n[c000200037fa7fe0] [c00000000000ded8] start_kernel_thread+0x14/0x18\n\nAllocated by task 1997 on cpu 1 at 35.928317s:\n\nThe buggy address belongs to the object at c00020003bda3000\n which belongs to the cache kmalloc-rnd-15-2k of size 2048\nThe buggy address is located 16 bytes to the right of\n allocated 1448-byte region [c00020003bda3000, c00020003bda35a8)\n\nThe buggy address belongs to the physical page:\n\nMemory state around the buggy address:\n c00020003bda3480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n c00020003bda3500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n>c00020003bda3580: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc\n                                        ^\n c00020003bda3600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n c00020003bda3680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n==================================================================\n\nFix this by allocating the flexible array using nr_node_ids instead\nof num_possible_nodes(). Since nr_node_ids represents the maximum\npossible NUMA node IDs, indexing current_path[] using numa_node_id()\nbecomes safe even on systems with sparse node IDs.","published":"2026-08-15T06:22:40.000Z","lastModified":"2026-10-16T19:17:43.000Z","status":"Received","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":[],"affected":[],"epss":{"score":0.00514,"percentile":0.43538,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/001e57554de81aa79c25c18fd53911d8a415c304","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/140d6fff4ed266592492a23444043842b4af7a62","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1d4131b5c9823c7d2c86389898ad1b466af7df5e","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/316b5f1168264844aa125959de1d6da2b1905795","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7173a741fed73de6247384056fe92e582ba12507","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7e7b167e65610dfa7564d449474f4b477f9d4c1c","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9ffdd11bd6c961b46b3689850ff6c5d7af5c5fe5","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bde4d6eb53f7d3cdae7e62c9ee84345fdd6e70a6","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74384","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}