GHSA-VX7W-47R6-WXW3
Vulnerability from github – Published: 2026-04-22 15:31 – Updated: 2026-04-28 12:31In the Linux kernel, the following vulnerability has been resolved:
tracing: Drain deferred trigger frees if kthread creation fails
Boot-time trigger registration can fail before the trigger-data cleanup kthread exists. Deferring those frees until late init is fine, but the post-boot fallback must still drain the deferred list if kthread creation never succeeds.
Otherwise, boot-deferred nodes can accumulate on trigger_data_free_list, later frees fall back to synchronously freeing only the current object, and the older queued entries are leaked forever.
To trigger this, add the following to the kernel command line:
trace_event=sched_switch trace_trigger=sched_switch.traceon,sched_switch.traceon
The second traceon trigger will fail and be freed. This triggers a NULL pointer dereference and crashes the kernel.
Keep the deferred boot-time behavior, but when kthread creation fails, drain the whole queued list synchronously. Do the same in the late-init drain path so queued entries are not stranded there either.
{
"affected": [],
"aliases": [
"CVE-2026-31481"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-22T14:16:45Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Drain deferred trigger frees if kthread creation fails\n\nBoot-time trigger registration can fail before the trigger-data cleanup\nkthread exists. Deferring those frees until late init is fine, but the\npost-boot fallback must still drain the deferred list if kthread\ncreation never succeeds.\n\nOtherwise, boot-deferred nodes can accumulate on\ntrigger_data_free_list, later frees fall back to synchronously freeing\nonly the current object, and the older queued entries are leaked\nforever.\n\nTo trigger this, add the following to the kernel command line:\n\n trace_event=sched_switch trace_trigger=sched_switch.traceon,sched_switch.traceon\n\nThe second traceon trigger will fail and be freed. This triggers a NULL\npointer dereference and crashes the kernel.\n\nKeep the deferred boot-time behavior, but when kthread creation fails,\ndrain the whole queued list synchronously. Do the same in the late-init\ndrain path so queued entries are not stranded there either.",
"id": "GHSA-vx7w-47r6-wxw3",
"modified": "2026-04-28T12:31:30Z",
"published": "2026-04-22T15:31:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31481"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/250ab25391edeeab8462b68be42e4904506c409c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/771624b7884a83bb9f922ae64ee41a5f8b7576c9"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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.