GHSA-QWJV-757X-9F99
Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-28 12:31In the Linux kernel, the following vulnerability has been resolved:
workqueue: Fix unbound pool lifetime for pending pwqs
KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq():
BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318
CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.0 #1 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: 0x0 (flush-8:0) Call Trace: dump_stack_lvl+0x53/0x70 print_report+0xce/0x610 kasan_report+0xce/0x100 _raw_spin_trylock+0x6d/0x120 pwq_dec_nr_in_flight+0x4b4/0xcb0 process_one_work+0x921/0x11a0 worker_thread+0x4d0/0xd20 kthread+0x2de/0x3c0 ret_from_fork+0x3aa/0x620 ret_from_fork_asm+0x1a/0x30
Allocated by task 311: alloc_pwq+0x439/0xca0 apply_wqattrs_prepare+0x75e/0xd10 apply_workqueue_attrs_locked+0x44/0xa0 wq_nice_store+0x350/0x450
Freed by task 0: kfree+0x127/0x3b0 rcu_core+0x523/0x1780 handle_softirqs+0x1b3/0x610
Last potentially related work creation: put_unbound_pool+0x3f3/0x7d0 pwq_release_workfn+0x494/0x8e0 kthread_worker_fn+0x1ff/0x790
Canceling the last inactive work skips pwq_dec_nr_active(), so an empty pwq can remain on pending_pwqs when its refcnt reaches zero. pwq_release_workfn() currently puts the pool before removing that pwq. If this drops the last pool reference, the pool can be RCU-freed while the pwq remains reachable, and node_activate_pending_pwq() may trylock the freed pool->lock.
Remove the pwq from pending_pwqs before putting the pool.
{
"affected": [],
"aliases": [
"CVE-2026-99103"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-28T11:17:29Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix unbound pool lifetime for pending pwqs\n\nKASAN reports a use-after-free of an unbound worker_pool in\nnode_activate_pending_pwq():\n\n BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120\n Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318\n\n CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.0 #1 PREEMPT(lazy)\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\n Workqueue: 0x0 (flush-8:0)\n Call Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x53/0x70\n print_report+0xce/0x610\n kasan_report+0xce/0x100\n _raw_spin_trylock+0x6d/0x120\n pwq_dec_nr_in_flight+0x4b4/0xcb0\n process_one_work+0x921/0x11a0\n worker_thread+0x4d0/0xd20\n kthread+0x2de/0x3c0\n ret_from_fork+0x3aa/0x620\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\n\n Allocated by task 311:\n alloc_pwq+0x439/0xca0\n apply_wqattrs_prepare+0x75e/0xd10\n apply_workqueue_attrs_locked+0x44/0xa0\n wq_nice_store+0x350/0x450\n\n Freed by task 0:\n kfree+0x127/0x3b0\n rcu_core+0x523/0x1780\n handle_softirqs+0x1b3/0x610\n\n Last potentially related work creation:\n put_unbound_pool+0x3f3/0x7d0\n pwq_release_workfn+0x494/0x8e0\n kthread_worker_fn+0x1ff/0x790\n\nCanceling the last inactive work skips pwq_dec_nr_active(), so an empty\npwq can remain on pending_pwqs when its refcnt reaches zero.\npwq_release_workfn() currently puts the pool before removing that pwq.\nIf this drops the last pool reference, the pool can be RCU-freed while\nthe pwq remains reachable, and node_activate_pending_pwq() may trylock\nthe freed pool-\u003elock.\n\nRemove the pwq from pending_pwqs before putting the pool.",
"id": "GHSA-qwjv-757x-9f99",
"modified": "2026-10-28T12:31:01Z",
"published": "2026-10-28T12:31:01Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99103"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d2ef2b9f4c084ab498494d26495a82f7e15407b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6741dd3fd38e47c08bc39d11ef5fa141fa6d0441"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9f5d5aef3072a33c6f9bfb954bb0cba1c2541849"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf9c8aaea0d47410df8708bec195889f3a85cd3c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f320b85c90fe5fc9d4d06badd450518323a94a7f"
}
],
"schema_version": "1.4.0",
"severity": []
}
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