CVE-2026-72343: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4xw9-57x7-f4g8",
  "modified" : "2026-08-17T06:33:24Z",
  "published" : "2026-08-15T06:32:21Z",
  "aliases" : [ "CVE-2026-72343" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix HV VHCA stats zero-sized buffer allocation\n\nmlx5e_hv_vhca_stats_create() is called from mlx5e_nic_enable(),\nbefore mlx5e_open(). At that point priv->stats_nch is still zero,\nbecause it is only ever incremented in mlx5e_channel_stats_alloc(),\nwhich is reached only from mlx5e_open_channel().\n\nmlx5e_hv_vhca_stats_buf_size() therefore returns 0, and\nkvzalloc(0, GFP_KERNEL) returns ZERO_SIZE_PTR ((void *)16) rather\nthan NULL. The \"if (!buf)\" guard does not catch this, and\nmlx5e_hv_vhca_stats_create() completes \"successfully\" with\npriv->stats_agent.buf set to ZERO_SIZE_PTR.\n\nOnce channels are opened (priv->stats_nch > 0) and the hypervisor\nenables stats reporting, mlx5e_hv_vhca_stats_work() recomputes\nbuf_len using the new non-zero stats_nch and calls\nmemset(buf, 0, buf_len) on ZERO_SIZE_PTR, faulting at address 0x10.\n\nAllocate the buffer based on priv->max_nch, which is set in\nmlx5e_priv_init() and is the upper bound on stats_nch:\n\n  - Add a separate helper mlx5e_hv_vhca_stats_buf_max_size() that\n    returns sizeof(per_ring_stats) * max(max_nch, stats_nch), and\n    use it for the kvzalloc() in mlx5e_hv_vhca_stats_create().\n  - Keep mlx5e_hv_vhca_stats_buf_size() (which returns based on\n    stats_nch) for the worker's active payload size, so the wire\n    format (block->rings = stats_nch) and the amount of data filled\n    by mlx5e_hv_vhca_fill_stats() are unchanged.\n\nThe max(max_nch, stats_nch) guard handles the rare case where\nmlx5e_attach_netdev() recomputes max_nch downward across a\ndetach/resume cycle while priv->stats_nch persists (mlx5e_detach_netdev\ndoes not call mlx5e_priv_cleanup, so stats_nch is only reset when\nthe netdev is destroyed). Without the guard, the worker could compute\nbuf_len from stats_nch and overrun the smaller buffer allocated based\non the reduced max_nch.\n\nAllocating a non-zero buffer also makes the kvzalloc() failure path in\nmlx5e_hv_vhca_stats_create() reachable for the first time: it returns\nearly without (re)creating the agent. Clear\npriv->stats_agent.{agent,buf} in mlx5e_hv_vhca_stats_destroy() after\nfreeing them, so that if a later create() bails out on this path, a\nsubsequent teardown does not double-free the stale agent/buffer left\nfrom a previous enable/disable cycle.\n\nThis mirrors the existing mlx5e pattern of preallocating arrays of\nsize max_nch (e.g. priv->channel_stats) and lazily populating\nentries up to stats_nch on demand.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-72343"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/22c1d5ecccf92c849bdca1556179aafc95794baf"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/25f6b929c7e379cbea7cb8caa67b49b2d1efae17"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/3b3a552cf88e10bb7bda88b29cf1fd8267043d50"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/5b927dcec5f1087942bf123a82e64a3f66475f01"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/abc4c56427f144c96b2827a4db3b90eb5b7349a2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-15T06:22:07Z"
  }
}