---
cve: "CVE-2026-74594"
severity: "HIGH"
cvss: 7.8
epss: "19.2%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-22 16:16:31"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T00:49:25+02:00"
---

# CVE-2026-74594

> 7.8 HIGH

## Beschreibung

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

sched/psi: Shut down rtpoll_timer in psi_cgroup_free()

psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath
and can race psi_trigger_destroy() taking down the last rtpoll trigger under
rtpoll_trigger_lock:

  psi_schedule_rtpoll_work()        psi_trigger_destroy()

  rcu_read_lock();
  task = rcu_dereference(rtpoll_task);
                                    rcu_assign_pointer(rtpoll_task, NULL);
                                    timer_delete(&rtpoll_timer);
  mod_timer(&rtpoll_timer, ...);
  rcu_read_unlock();
                                    synchronize_rcu();
                                    kthread_stop(task_to_destroy);

The group can then be freed with the re-armed timer still pending, and
poll_timer_fn() runs on freed memory.

461daba06bdc ("psi: eliminate kthread_worker from psi trigger scheduling
mechanism") deleted the timer synchronously after the synchronize_rcu(),
which prevented this but raced trigger creation instead: the deletion could
cancel the timer that a new trigger set armed during the grace period and,
as creation also reinitialized the timer at the time, corrupt it.
8f91efd870ea ("psi: Fix race between psi_trigger_create/destroy") moved the
initialization into group_init() and the deletion into the locked section,
trading the creation races for the window above.

Neither placement in the destruction path works. A pending timer firing
while the group is alive is harmless though. poll_timer_fn() just wakes the
rtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's
lifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it
by then. timer_shutdown_sync() because the timer is never armed again.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.266
- Kernel ≥ 5.15.217
- Kernel ≥ 6.1.183
- Kernel ≥ 6.6.152
- Kernel ≥ 6.12.104
- Kernel ≥ 6.18.45
- Kernel ≥ 7.1.9

## Referenzen

- <https://git.kernel.org/stable/c/1e5ca82eee59caca6988f9d6e859786aab8a5fa0>
- <https://git.kernel.org/stable/c/310b5a537a78c358a4cd244bd767c1a517a05459>
- <https://git.kernel.org/stable/c/4addb102154b7cf6e2310ccbe20c3c08619e520d>
- <https://git.kernel.org/stable/c/5457025fa8ca3c0d2732109513de839e3e797190>
- <https://git.kernel.org/stable/c/611e7821c4f83a671455658797336faecc3a5196>
- <https://git.kernel.org/stable/c/8037c5b2b2a447df52542f4d8535895d837bdcbd>
- <https://git.kernel.org/stable/c/806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08>
- <https://git.kernel.org/stable/c/894a9300d7fb2e2951da92e565ae6de7ddfb0a69>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-74594) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_