CVE-2026-64424 (GCVE-0-2026-64424)
Vulnerability from cvelistv5
Published
2026-07-25 08:51
Modified
2026-08-17 04:55
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
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"versions": [
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"version": "0",
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"version": "6.12.96",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.1.4",
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"descriptions": [
{
"lang": "en",
"value": "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."
}
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"dateUpdated": "2026-08-17T04:55:24.351Z",
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"url": "https://git.kernel.org/stable/c/95ecc5b58042f6b6743b589e6588f1cd7ba336aa"
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"url": "https://git.kernel.org/stable/c/a33f37f8d079da7236ed7b7e2aed2a34ab81e7cf"
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"url": "https://git.kernel.org/stable/c/5ed09a108d93a3b002cc79823d9455b50c4a8be7"
},
{
"url": "https://git.kernel.org/stable/c/45f1458a85017a023f138b22ac5c76abd477db42"
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],
"title": "netpoll: fix a use-after-free on shutdown path",
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"cveId": "CVE-2026-64424",
"datePublished": "2026-07-25T08:51:02.276Z",
"dateReserved": "2026-07-19T15:36:31.787Z",
"dateUpdated": "2026-08-17T04:55:24.351Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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