# CVE-2026-90305: linux: In the Linux kernel, the following vulnerability has been resolved:  ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_W...

CVE-2026-90305 is fixed in linux on 1 platform by DEBIAN-CVE-2026-90305 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-90305
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK  Commit c6e61c06d606 ("ARM: 9463/1: Allow to enable RT") enabled PREEMPT_RT on ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves CONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard IRQ context.  On PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping sighand->siglock:    BUG: sleeping function called from invalid context at spinlock_rt.c:48     rt_spin_lock from lock_task_sighand     lock_task_sighand from run_posix_cpu_timers     run_posix_cpu_timers from update_process_times  ARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M. ARM32 KVM host support was removed by commit 541ad0150ca4 ("arm: Remove 32bit KVM host support"), so the select need not be conditional on KVM.  Select it to defer POSIX CPU timer expiry to task context.  Reproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path is used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers created with timer_create().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-90305](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90305.md) | Sep 23, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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