GHSA-8FFV-2J52-H7H3
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-09-03 15:32In the Linux kernel, the following vulnerability has been resolved:
irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT
On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0.
After irq_work_single() clears BUSY via atomic_cmpxchg(), it still dereferences @work for irq_work_is_hard() and rcuwait_wake_up().
An irq_work_sync() caller on another CPU that enters after BUSY is cleared can observe BUSY==0 immediately, return, and free the work before those accesses complete — causing a use-after-free.
Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire irq_work_single() execution is within an RCU read-side critical section. Then add synchronize_rcu() in irq_work_sync() after rcuwait_wait_event() to ensure the caller waits for the RCU grace period before returning, preventing premature frees.
{
"affected": [],
"aliases": [
"CVE-2026-64073"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:47Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nirq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT\n\nOn PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via\nrun_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0.\n\nAfter irq_work_single() clears BUSY via atomic_cmpxchg(), it still\ndereferences @work for irq_work_is_hard() and rcuwait_wake_up().\n\nAn irq_work_sync() caller on another CPU that enters after BUSY is cleared\ncan observe BUSY==0 immediately, return, and free the work before those\naccesses complete \u2014 causing a use-after-free.\n\nFix this by wrapping run_irq_workd() in guard(rcu)() so that the entire\nirq_work_single() execution is within an RCU read-side critical\nsection. Then add synchronize_rcu() in irq_work_sync() after\nrcuwait_wait_event() to ensure the caller waits for the RCU grace period\nbefore returning, preventing premature frees.",
"id": "GHSA-8ffv-2j52-h7h3",
"modified": "2026-09-03T15:32:00Z",
"published": "2026-07-19T18:31:51Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64073"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/18c0456ea2615b1a743a6db739c74411c3b42bc6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2dc79362302922cb18f35e262712b5e58de65442"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/684a78183c54c23e70d1cba320f7fc184604210b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/81b582784518196eff1050212a046bc29d3a05dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/91840be8f710370607f949a627e070896faeddb8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eef4f71b46a9929ac33e968538c9dd5d96a02460"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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