Vulnerability-Lookup

GHSA-8P49-RXQC-9388

Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-17 18:31

Details

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().

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{
  "affected": [],
  "aliases": [
    "CVE-2026-90305"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-17T17:17:28Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK\n\nCommit c6e61c06d606 (\"ARM: 9463/1: Allow to enable RT\") enabled PREEMPT_RT\non ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves\nCONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard\nIRQ context.\n\nOn PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping\nsighand-\u003esiglock:\n\n  BUG: sleeping function called from invalid context at spinlock_rt.c:48\n    rt_spin_lock from lock_task_sighand\n    lock_task_sighand from run_posix_cpu_timers\n    run_posix_cpu_timers from update_process_times\n\nARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M.\nARM32 KVM host support was removed by commit 541ad0150ca4 (\"arm: Remove\n32bit KVM host support\"), so the select need not be conditional on KVM.\n\nSelect it to defer POSIX CPU timer expiry to task context.\n\nReproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path\nis used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers\ncreated with timer_create().",
  "id": "GHSA-8p49-rxqc-9388",
  "modified": "2026-09-17T18:31:59Z",
  "published": "2026-09-17T18:31:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90305"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a58a41100ea377e978d99600ec24a9bd0273662"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8de56782d6e5ba7a9f8c820342dccde65502f93f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-90305 (GCVE-0-2026-90305)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:08 – Updated: 2026-09-17 16:08

Title

ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK

Summary

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().

Severity

No CVSS data available.

Assigner

Linux mitre root Scorecard

References

2 references

URL	Tags
https://git.kernel.org/stable/c/8de56782d6e5ba7a9…
https://git.kernel.org/stable/c/8a58a41100ea377e9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c6e61c06d6061750597e79c598acb5dead44c35b , < 8de56782d6e5ba7a9f8c820342dccde65502f93f (git) Affected: c6e61c06d6061750597e79c598acb5dead44c35b , < 8a58a41100ea377e978d99600ec24a9bd0273662 (git)
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
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          "programFiles": [
            "arch/arm/Kconfig"
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
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          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
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              "status": "unaffected",
              "version": "0",
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.3-rc1",
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        }
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      "cpeApplicability": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK\n\nCommit c6e61c06d606 (\"ARM: 9463/1: Allow to enable RT\") enabled PREEMPT_RT\non ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves\nCONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard\nIRQ context.\n\nOn PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping\nsighand-\u003esiglock:\n\n  BUG: sleeping function called from invalid context at spinlock_rt.c:48\n    rt_spin_lock from lock_task_sighand\n    lock_task_sighand from run_posix_cpu_timers\n    run_posix_cpu_timers from update_process_times\n\nARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M.\nARM32 KVM host support was removed by commit 541ad0150ca4 (\"arm: Remove\n32bit KVM host support\"), so the select need not be conditional on KVM.\n\nSelect it to defer POSIX CPU timer expiry to task context.\n\nReproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path\nis used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers\ncreated with timer_create()."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:08:27.742Z",
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/8a58a41100ea377e978d99600ec24a9bd0273662"
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    "assignerShortName": "Linux",
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    "datePublished": "2026-09-17T16:08:27.742Z",
    "dateReserved": "2026-09-11T19:38:34.800Z",
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    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-8P49-RXQC-9388

CVE-2026-90305 (GCVE-0-2026-90305)

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