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GHSA-4M75-5382-C595

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

netpoll: fix a use-after-free on shutdown path

There is a use-after-free error on netpoll, which is clearly detected by KASAN.

  BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3b/0x80
  Read of size 1 at addr ... by task kworker/9:1
  Workqueue: events queue_process
  Call Trace:
   skb_dequeue+0x1e/0xb0
   queue_process+0x2c/0x600
   process_scheduled_works+0x4b6/0x850
   worker_thread+0x414/0x5a0
  Allocated by task 242:
   __netpoll_setup+0x201/0x4a0
   netpoll_setup+0x249/0x550
   enabled_store+0x32f/0x380
  Freed by task 0:
   kfree+0x1b7/0x540
   rcu_core+0x3f8/0x7a0

The problem happens when there is a pending TX worker running in parallel with the cleanup path.

This is what happens on netpoll shutdown path:

1) __netpoll_cleanup() is called 2) set dev->npinfo to NULL 3) call_rcu() with rcu_cleanup_netpoll_info() 3.1) rcu_cleanup_netpoll_info() tries to cancel all workers with cancel_delayed_work(), but doesn't wait for the worker to finish 4) and kfree(npinfo);

Because 3.1) doesn't really cancel the work, as the comment says "we can't call cancel_delayed_work_sync here, as we are in softirq", the TX worker can run after 4).

Tl;DR: queue_process() is not an RCU reader, it reaches npinfo through the work item via container_of().

Use disable_delayed_work_sync() to ensure the worker is completely stopped and prevent any future re-arming attempts. Once npinfo is set to NULL, senders will bail out and not queue new work. The disable flag ensures any in-flight re-arming attempts also fail silently.

In the future, we can do the cleanup inline here without needing the npinfo->rcu rcu_head, but that is net-next material.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64424"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:26Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetpoll: fix a use-after-free on shutdown path\n\nThere is a use-after-free error on netpoll, which is clearly detected by\nKASAN.\n\n      BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3b/0x80\n      Read of size 1 at addr ... by task kworker/9:1\n      Workqueue: events queue_process\n      Call Trace:\n       skb_dequeue+0x1e/0xb0\n       queue_process+0x2c/0x600\n       process_scheduled_works+0x4b6/0x850\n       worker_thread+0x414/0x5a0\n      Allocated by task 242:\n       __netpoll_setup+0x201/0x4a0\n       netpoll_setup+0x249/0x550\n       enabled_store+0x32f/0x380\n      Freed by task 0:\n       kfree+0x1b7/0x540\n       rcu_core+0x3f8/0x7a0\n\nThe problem happens when there is a pending TX worker running in\nparallel with the cleanup path.\n\nThis is what happens on netpoll shutdown path:\n\n1) __netpoll_cleanup() is called\n2) set dev-\u003enpinfo to NULL\n3) call_rcu() with rcu_cleanup_netpoll_info()\n  3.1) rcu_cleanup_netpoll_info() tries to cancel all workers with\n       cancel_delayed_work(), but doesn\u0027t wait for the worker to finish\n4) and kfree(npinfo);\n\nBecause 3.1) doesn\u0027t really cancel the work, as the comment says \"we\ncan\u0027t call cancel_delayed_work_sync here, as we are in softirq\", the TX\nworker can run after 4).\n\nTl;DR: queue_process() is not an RCU reader, it reaches npinfo through\nthe work item via container_of().\n\nUse disable_delayed_work_sync() to ensure the worker is completely\nstopped and prevent any future re-arming attempts. Once npinfo is set\nto NULL, senders will bail out and not queue new work. The disable flag\nensures any in-flight re-arming attempts also fail silently.\n\nIn the future, we can do the cleanup inline here without needing the\nnpinfo-\u003ercu rcu_head, but that is net-next material.",
  "id": "GHSA-4m75-5382-c595",
  "modified": "2026-07-25T12:31:35Z",
  "published": "2026-07-25T12:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64424"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/45f1458a85017a023f138b22ac5c76abd477db42"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ed09a108d93a3b002cc79823d9455b50c4a8be7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95ecc5b58042f6b6743b589e6588f1cd7ba336aa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a33f37f8d079da7236ed7b7e2aed2a34ab81e7cf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64424 (GCVE-0-2026-64424)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:51 – Updated: 2026-07-25 08:51

Title

netpoll: fix a use-after-free on shutdown path

Summary

In the Linux kernel, the following vulnerability has been resolved: netpoll: fix a use-after-free on shutdown path There is a use-after-free error on netpoll, which is clearly detected by KASAN. BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3b/0x80 Read of size 1 at addr ... by task kworker/9:1 Workqueue: events queue_process Call Trace: skb_dequeue+0x1e/0xb0 queue_process+0x2c/0x600 process_scheduled_works+0x4b6/0x850 worker_thread+0x414/0x5a0 Allocated by task 242: __netpoll_setup+0x201/0x4a0 netpoll_setup+0x249/0x550 enabled_store+0x32f/0x380 Freed by task 0: kfree+0x1b7/0x540 rcu_core+0x3f8/0x7a0 The problem happens when there is a pending TX worker running in parallel with the cleanup path. This is what happens on netpoll shutdown path: 1) __netpoll_cleanup() is called 2) set dev->npinfo to NULL 3) call_rcu() with rcu_cleanup_netpoll_info() 3.1) rcu_cleanup_netpoll_info() tries to cancel all workers with cancel_delayed_work(), but doesn't wait for the worker to finish 4) and kfree(npinfo); Because 3.1) doesn't really cancel the work, as the comment says "we can't call cancel_delayed_work_sync here, as we are in softirq", the TX worker can run after 4). Tl;DR: queue_process() is not an RCU reader, it reaches npinfo through the work item via container_of(). Use disable_delayed_work_sync() to ensure the worker is completely stopped and prevent any future re-arming attempts. Once npinfo is set to NULL, senders will bail out and not queue new work. The disable flag ensures any in-flight re-arming attempts also fail silently. In the future, we can do the cleanup inline here without needing the npinfo->rcu rcu_head, but that is net-next material.

Severity

No CVSS data available.

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/95ecc5b58042f6b67…
https://git.kernel.org/stable/c/a33f37f8d079da723…
https://git.kernel.org/stable/c/5ed09a108d93a3b00…
https://git.kernel.org/stable/c/45f1458a85017a023…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 38e6bc185d9544dfad1774b3f8902a0b061aea25 , < 95ecc5b58042f6b6743b589e6588f1cd7ba336aa (git) Affected: 38e6bc185d9544dfad1774b3f8902a0b061aea25 , < a33f37f8d079da7236ed7b7e2aed2a34ab81e7cf (git) Affected: 38e6bc185d9544dfad1774b3f8902a0b061aea25 , < 5ed09a108d93a3b002cc79823d9455b50c4a8be7 (git) Affected: 38e6bc185d9544dfad1774b3f8902a0b061aea25 , < 45f1458a85017a023f138b22ac5c76abd477db42 (git)
Linux	Linux	Affected: 3.6 Unaffected: 0 , < 3.6 (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc2 , ≤ * (original_commit_for_fix)

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JSON

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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/netpoll.c"
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.6"
            },
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              "status": "unaffected",
              "version": "0",
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              "version": "6.18.39",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
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            }
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "3.6",
                  "vulnerable": true
                },
                {
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        {
          "url": "https://git.kernel.org/stable/c/45f1458a85017a023f138b22ac5c76abd477db42"
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    "datePublished": "2026-07-25T08:51:02.276Z",
    "dateReserved": "2026-07-19T15:36:31.787Z",
    "dateUpdated": "2026-07-25T08:51:02.276Z",
    "state": "PUBLISHED"
  },
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

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GHSA-4M75-5382-C595

CVE-2026-64424 (GCVE-0-2026-64424)

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