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CVE-2026-74384

Status: ReceivedCritical (9.8)—

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()]

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.

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.

Read full descriptionShow less

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:

Fix this by allocating the flexible array using nr_node_ids instead of num_possible_nodes(). Since nr_node_ids represents the maximum possible NUMA node IDs, indexing current_path[] using numa_node_id() becomes safe even on systems with sparse node IDs.

Technical details traces, logs and code from the original report
The structure is currently allocated as:
size = sizeof(struct nvme_ns_head) +
       (num_possible_nodes() * sizeof(struct nvme_ns *));
head = kzalloc(size, GFP_KERNEL);

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):

==================================================================
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: 1997 Comm: kworker/u641:2 Not tainted 7.1.0-rc5-dirty #14 PREEMPT(lazy)
Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV
Workqueue: async async_run_entry_fn
Call Trace:
[c000200037fa7510] [c0000000021c23d4] dump_stack_lvl+0x88/0xdc (unreliable)
[c000200037fa7540] [c0000000009fda90] print_report+0x22c/0x67c
[c000200037fa7630] [c0000000009fd508] kasan_report+0x108/0x220
[c000200037fa7740] [c0000000009fff48] __asan_store8+0xe8/0x120
[c000200037fa7760] [c008000018e76474] nvme_mpath_revalidate_paths+0x22c/0x290 [nvme_core]
[c000200037fa7800] [c008000018e6556c] nvme_update_ns_info+0x4a4/0x5e0 [nvme_core]
[c000200037fa7a50] [c008000018e66270] nvme_alloc_ns+0x6d8/0x1a70 [nvme_core]
[c000200037fa7c20] [c008000018e679fc] nvme_scan_ns+0x3f4/0x630 [nvme_core]
[c000200037fa7d10] [c00000000031f22c] async_run_entry_fn+0x9c/0x3a0
[c000200037fa7db0] [c0000000002fa544] process_one_work+0x414/0xa10
[c000200037fa7ec0] [c0000000002fbf00] worker_thread+0x320/0x640
[c000200037fa7f80] [c00000000030d0f8] kthread+0x278/0x290
[c000200037fa7fe0] [c00000000000ded8] start_kernel_thread+0x14/0x18

Allocated by task 1997 on cpu 1 at 35.928317s:

The buggy address belongs to the object at c00020003bda3000
 which belongs to the cache kmalloc-rnd-15-2k of size 2048
The buggy address is located 16 bytes to the right of
 allocated 1448-byte region [c00020003bda3000, c00020003bda35a8)

The buggy address belongs to the physical page:

Memory state around the buggy address:
 c00020003bda3480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 c00020003bda3500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>c00020003bda3580: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
                                        ^
 c00020003bda3600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 c00020003bda3680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vulnerabilidad de desbordamiento de búfer en kernel Linux (AV:N/AC:L/PR:N/UI:N). Acceso remoto a código arbitrario o escalada de privilegios; posible DoS por corrupción de memoria en subsistema nvme-multipath.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network TrafficApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareVulnerability ScanningThreat Intelligence Program

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-74384",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "7e7b167e65610dfa7564d449474f4b477f9d4c1c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "316b5f1168264844aa125959de1d6da2b1905795",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "1d4131b5c9823c7d2c86389898ad1b466af7df5e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "9ffdd11bd6c961b46b3689850ff6c5d7af5c5fe5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "bde4d6eb53f7d3cdae7e62c9ee84345fdd6e70a6",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "140d6fff4ed266592492a23444043842b4af7a62",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "7173a741fed73de6247384056fe92e582ba12507",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f333444708f82c4a4d3ccac004da0bfd9cfdfa42",
              "lessThan": "001e57554de81aa79c25c18fd53911d8a415c304",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/nvme/host/core.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.20",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/nvme/host/core.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:40.270",
  "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"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "lastModified": "2026-08-17T06:19:33.300",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}