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FKIE_CVE-2026-72342

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:18
Severity
8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats agent registration race mlx5e_hv_vhca_stats_create() registers the stats agent through mlx5_hv_vhca_agent_create(). The helper publishes the agent in hv_vhca->agents[type] under agents_lock and immediately schedules an asynchronous control invalidation on the HV VHCA workqueue before returning to mlx5e. The asynchronous invalidation invokes the control agent's invalidate callback, which reads the hypervisor control block and forwards the command to mlx5e_hv_vhca_stats_control(). That callback may either: - call cancel_delayed_work_sync(&priv->stats_agent.work), or - call queue_delayed_work(priv->wq, &sagent->work, sagent->delay). However, the delayed_work and priv->stats_agent.agent are only initialized after mlx5_hv_vhca_agent_create() returns to mlx5e: agent = mlx5_hv_vhca_agent_create(...); /* publish + invalidate */ ... priv->stats_agent.agent = agent; /* too late */ INIT_DELAYED_WORK(&priv->stats_agent.work, ...); /* too late */ If the asynchronous control path runs before the two assignments above, it can: - Operate on an uninitialized delayed_work whose timer.function is NULL. queue_delayed_work() calls add_timer() unconditionally, so when the timer expires the timer softirq invokes a NULL function pointer. - Re-initialize the timer later through INIT_DELAYED_WORK() while the timer is already enqueued in the timer wheel, corrupting the hlist (entry.pprev cleared while the previous bucket node still points at this entry). - When the worker eventually runs, mlx5e_hv_vhca_stats_work() reads sagent->agent (NULL) and dereferences it inside mlx5_hv_vhca_agent_write(). Fix this by: - Initializing priv->stats_agent.work before invoking mlx5_hv_vhca_agent_create(), so the work is always in a valid state when the control callback observes it. - Adding a struct mlx5_hv_vhca_agent **ctx_update out-parameter to mlx5_hv_vhca_agent_create(). The helper writes the agent pointer to *ctx_update before publishing into hv_vhca->agents[] and triggering the agents_update flow, so any callback subsequently invoked from that flow already sees a valid priv->stats_agent.agent. This avoids having the control callback participate in agent initialization. While at it, access priv->stats_agent.agent with READ_ONCE()/WRITE_ONCE() for the cross-CPU access with the worker, and clear priv->stats_agent.buf on the agent_create() failure path.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/60fddda7207d81fea71463abd403f0b10f74f2e1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/89b25b5f46f488ea3b29b3444864c76944c9075b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b0fd6d3bb06182f19f3b59a53f57b5098b99048a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f5677797b094c3ec5fb350eb8ea7710b88a3d018
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c",
            "drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.c",
            "drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b0fd6d3bb06182f19f3b59a53f57b5098b99048a",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            },
            {
              "lessThan": "24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            },
            {
              "lessThan": "e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            },
            {
              "lessThan": "60fddda7207d81fea71463abd403f0b10f74f2e1",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            },
            {
              "lessThan": "f5677797b094c3ec5fb350eb8ea7710b88a3d018",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            },
            {
              "lessThan": "89b25b5f46f488ea3b29b3444864c76944c9075b",
              "status": "affected",
              "version": "cef35af34d6dc3792333075115c7deb7062b6e18",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c",
            "drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.c",
            "drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.4"
            },
            {
              "lessThan": "5.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix HV VHCA stats agent registration race\n\nmlx5e_hv_vhca_stats_create() registers the stats agent through\nmlx5_hv_vhca_agent_create(). The helper publishes the agent in\nhv_vhca-\u003eagents[type] under agents_lock and immediately schedules an\nasynchronous control invalidation on the HV VHCA workqueue before\nreturning to mlx5e.\n\nThe asynchronous invalidation invokes the control agent\u0027s invalidate\ncallback, which reads the hypervisor control block and forwards the\ncommand to mlx5e_hv_vhca_stats_control(). That callback may either:\n\n  - call cancel_delayed_work_sync(\u0026priv-\u003estats_agent.work), or\n  - call queue_delayed_work(priv-\u003ewq, \u0026sagent-\u003ework, sagent-\u003edelay).\n\nHowever, the delayed_work and priv-\u003estats_agent.agent are only\ninitialized after mlx5_hv_vhca_agent_create() returns to mlx5e:\n\n    agent = mlx5_hv_vhca_agent_create(...);   /* publish + invalidate */\n    ...\n    priv-\u003estats_agent.agent = agent;          /* too late */\n    INIT_DELAYED_WORK(\u0026priv-\u003estats_agent.work, ...); /* too late */\n\nIf the asynchronous control path runs before the two assignments\nabove, it can:\n\n  - Operate on an uninitialized delayed_work whose timer.function is\n    NULL. queue_delayed_work() calls add_timer() unconditionally, so\n    when the timer expires the timer softirq invokes a NULL function\n    pointer.\n  - Re-initialize the timer later through INIT_DELAYED_WORK() while\n    the timer is already enqueued in the timer wheel, corrupting the\n    hlist (entry.pprev cleared while the previous bucket node still\n    points at this entry).\n  - When the worker eventually runs, mlx5e_hv_vhca_stats_work() reads\n    sagent-\u003eagent (NULL) and dereferences it inside\n    mlx5_hv_vhca_agent_write().\n\nFix this by:\n\n  - Initializing priv-\u003estats_agent.work before invoking\n    mlx5_hv_vhca_agent_create(), so the work is always in a valid\n    state when the control callback observes it.\n  - Adding a struct mlx5_hv_vhca_agent **ctx_update out-parameter\n    to mlx5_hv_vhca_agent_create(). The helper writes the agent\n    pointer to *ctx_update before publishing into hv_vhca-\u003eagents[]\n    and triggering the agents_update flow, so any callback\n    subsequently invoked from that flow already sees a valid\n    priv-\u003estats_agent.agent. This avoids having the control\n    callback participate in agent initialization.\n\nWhile at it, access priv-\u003estats_agent.agent with\nREAD_ONCE()/WRITE_ONCE() for the cross-CPU access with the worker, and\nclear priv-\u003estats_agent.buf on the agent_create() failure path."
    }
  ],
  "id": "CVE-2026-72342",
  "lastModified": "2026-08-17T06:18:38.010",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:22:07.520",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/60fddda7207d81fea71463abd403f0b10f74f2e1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/89b25b5f46f488ea3b29b3444864c76944c9075b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b0fd6d3bb06182f19f3b59a53f57b5098b99048a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f5677797b094c3ec5fb350eb8ea7710b88a3d018"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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