net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation

{
  "id": "da4492be9ae0c4519d7256487a835e556eeed072e47982e85223e47d3ff78282",
  "url": "https://osv.dev/vulnerability/CVE-2026-72343",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation mlx5e_hv_vhca_stats_create() is called from mlx5e_nic_enable(), before mlx5e_open(). At that point priv->stats_nch is still zero, because it is only ever incremented in mlx5e_channel_stats_alloc(), which is reached only from mlx5e_open_channel(). mlx5e_hv_vhca_stats_buf_size() therefore returns 0, and kvzalloc(0, GFP_KERNEL) returns ZERO_SIZE_PTR ((void *)16) rather than NULL. The \"if (!buf)\" guard does not catch this, and mlx5e_hv_vhca_stats_create() completes \"successfully\" with priv->stats_agent.buf set to ZERO_SIZE_PTR. Once channels are opened (priv->stats_nch > 0) and the hypervisor enables stats reporting, mlx5e_hv_vhca_stats_work() recomputes buf_len using the new non-zero stats_nch and calls memset(buf, 0, buf_len) on ZERO_SIZE_PTR, faulting at address 0x10. Allocate the buffer based on priv->max_nch, which is set in mlx5e_priv_init() and is the upper bound on stats_nch: - Add a separate helper mlx5e_hv_vhca_stats_buf_max_size() that returns sizeof(per_ring_stats) * max(max_nch, stats_nch), and use it for the kvzalloc() in mlx5e_hv_vhca_stats_create(). - Keep mlx5e_hv_vhca_stats_buf_size() (which returns based on stats_nch) for the worker's active payload size, so the wire format (block->rings = stats_nch) and the amount of data filled by mlx5e_hv_vhca_fill_stats() are unchanged. The max(max_nch, stats_nch) guard handles the rare case where ml",
    "evidence": "osv:CVE-2026-72343",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-72343",
      "aliases": [
        "CVE-2026-72343"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "3b3a552cf88e10bb7bda88b29cf1fd8267043d50"
                },
                {
                  "fixed": "5b927dcec5f1087942bf123a82e64a3f66475f01"
                },
                {
                  "fixed": "22c1d5ecccf92c849bdca1556179aafc95794baf"
                },
                {
                  "fixed": "420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4"
                },
                {
                  "fixed": "abc4c56427f144c96b2827a4db3b90eb5b7349a2"
                },
                {
                  "fixed": "25f6b929c7e379cbea7cb8caa67b49b2d1efae17"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72343.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.17.0"
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                {
                  "fixed": "6.1.178"
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.2.0"
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            {
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            {
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.19.0"
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                {
                  "fixed": "7.1.5"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72343.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.959124520Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/22c1d5ecccf92c849bdca1556179aafc95794baf",
        "https://git.kernel.org/stable/c/25f6b929c7e379cbea7cb8caa67b49b2d1efae17",
        "https://git.kernel.org/stable/c/3b3a552cf88e10bb7bda88b29cf1fd8267043d50",
        "https://git.kernel.org/stable/c/420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4",
        "https://git.kernel.org/stable/c/5b927dcec5f1087942bf123a82e64a3f66475f01",
        "https://git.kernel.org/stable/c/abc4c56427f144c96b2827a4db3b90eb5b7349a2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72343.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72343",
        "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/2026/72xxx/CVE-2026-72343.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72343",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495866,
  "published_at": "2026-08-15T05:55:49.067+00:00"
}