nvme-multipath: fix flex array size in struct nvme_ns_head

{
  "id": "ddaa61f96731026596f5468ca9aae7e2f811723edf513d9f2ec20184767eeaa6",
  "url": "https://osv.dev/vulnerability/CVE-2026-74384",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nvme-multipath: fix flex array size in struct nvme_ns_head",
    "summary": "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: head->current_path[numa_node_id()] The structure is currently allocated as: size = sizeof(struct nvme_ns_head) + (num_possible_nodes() * sizeof(struct nvme_ns *)); head = kzalloc(size, GFP_KERNEL); This allocation assumes that NUMA node IDs are sequential and densely packed from 0 .. num_possible_nodes() - 1. While this assumption holds on many systems, it is not always true on some architectures such as powerpc. On some powerpc systems, NUMA node IDs can be sparse. For example: NUMA: NUMA node(s): 6 NUMA node0 CPU(s): 80-159 NUMA node8 CPU(s): 0-79 NUMA node252 CPU(s): NUMA node253 CPU(s): NUMA node254 CPU(s): NUMA node255 CPU(s): That is, the possible/online NUMA node IDs are: 0, 8, 252, 253, 254, 255 In this case: num_possible_nodes() = 6 So memory is allocated for only 6 entries in current_path[]. However, the array is later indexed using the actual NUMA node ID. As a result, accesses such as: head->current_path[8] or head->current_path[252] goes out of bounds, leading to the following KASAN splat: ================================================================== BUG: KASAN: slab-out-of-bounds in nvme_mpath_revalidate_paths+0x22c/0x290 [nvme_core] Write of size 8 at addr c00020003bda35b8 by task kworker/u641:2/1997 CPU: 1 UID: 0 PID: 199",
    "evidence": "osv:CVE-2026-74384",
    "products": [
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        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
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        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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    "severity": "critical",
    "structured": {
      "id": "CVE-2026-74384",
      "aliases": [
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      "metrics": [
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          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
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      "modified": "2026-10-28T02:30:35.528285732Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/001e57554de81aa79c25c18fd53911d8a415c304",
        "https://git.kernel.org/stable/c/140d6fff4ed266592492a23444043842b4af7a62",
        "https://git.kernel.org/stable/c/1d4131b5c9823c7d2c86389898ad1b466af7df5e",
        "https://git.kernel.org/stable/c/316b5f1168264844aa125959de1d6da2b1905795",
        "https://git.kernel.org/stable/c/7173a741fed73de6247384056fe92e582ba12507",
        "https://git.kernel.org/stable/c/7e7b167e65610dfa7564d449474f4b477f9d4c1c",
        "https://git.kernel.org/stable/c/9ffdd11bd6c961b46b3689850ff6c5d7af5c5fe5",
        "https://git.kernel.org/stable/c/bde4d6eb53f7d3cdae7e62c9ee84345fdd6e70a6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74384.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74384",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74384.json"
      }
    },
    "related_cves": [
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        "value": "CVE-2026-74384",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 502975,
  "published_at": "2026-08-15T05:59:00.445+00:00"
}