CVE-2026-99093 (GCVE-0-2026-99093)

Vulnerability from cvelistv5 – Published: 2026-10-26 14:52 – Updated: 2026-10-26 14:52
VLAI
Title
mm: don't schedule deferred kernel page table freeing while booting
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: don't schedule deferred kernel page table freeing while booting Booting with a boot-time function tracer and a filter, for example ftrace=function ftrace_filter=pud_free_pmd_page panics on 7.3-rc4 as soon as the tracer starts: [ 23.531178] Starting tracer 'function' [ 23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI [ 23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7] [ 23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef) [ 24.252248] RIP: 0010:__queue_work+0xab/0xf00 [ 25.981629] Call Trace: [ 26.125727] <TASK> [ 26.413912] ? pagetable_free_kernel+0x20/0x120 [ 26.990283] queue_work_on+0x97/0xf0 [ 27.134382] __cpa_collapse_large_pages+0x501/0x6f0 [ 27.566662] cpa_flush+0x394/0x620 [ 27.998953] change_page_attr_set_clr+0x321/0x4a0 [ 29.151729] set_memory_rox+0xa2/0xf0 [ 29.584018] create_trampoline+0x431/0x6f0 ... [ 44.343347] Kernel panic - not syncing: Attempted to kill the idle task! The boot-time tracer is started from early_trace_init(), which runs before workqueue_init_early(). Making its trampoline read-only splits a large page, and CPA collapses it again right away. The split table has been a kernel page table since commit 9e4a3ec3411b ("x86/mm/pat: Allocate split page tables as kernel page tables"), so the collapse frees it through pagetable_free_kernel(), which queues work on system_percpu_wq - still NULL at that point. That commit is correct in itself; it only lets CPA reach pagetable_free_kernel() before the workqueue that function relies on exists. Keep putting the table on the list, but don't schedule the work while the system is still booting. A core_initcall schedules it once to free whatever was queued by then.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 84e0cd79d57f06b872154eb5d8f610584133f260 , < 7a25ca170c12a9328f6fcf4410713beb516b01c0 (git)
Affected: 922873cf4fc34124215070a8ad391bf831538bb9 , < df6c704a08bc0925d5db047b0a6221f962bda4d9 (git)
Affected: 9e4a3ec3411bb6bb59e3c1f29b75609f1e87aac4 , < 2fb552b0bee70c24c092720028ab4620f5eb2646 (git)
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Linux Linux Affected: 6.18.53 , < 6.18.57 (semver)
Affected: 7.2.7 , < 7.2.11 (semver)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/pgtable-generic.c"
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              "versionType": "git"
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                  "vulnerable": true
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: don\u0027t schedule deferred kernel page table freeing while booting\n\nBooting with a boot-time function tracer and a filter, for example\n\n  ftrace=function ftrace_filter=pud_free_pmd_page\n\npanics on 7.3-rc4 as soon as the tracer starts:\n\n  [   23.531178] Starting tracer \u0027function\u0027\n  [   23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI\n  [   23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]\n  [   23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef)\n  [   24.252248] RIP: 0010:__queue_work+0xab/0xf00\n  [   25.981629] Call Trace:\n  [   26.125727]  \u003cTASK\u003e\n  [   26.413912]  ? pagetable_free_kernel+0x20/0x120\n  [   26.990283]  queue_work_on+0x97/0xf0\n  [   27.134382]  __cpa_collapse_large_pages+0x501/0x6f0\n  [   27.566662]  cpa_flush+0x394/0x620\n  [   27.998953]  change_page_attr_set_clr+0x321/0x4a0\n  [   29.151729]  set_memory_rox+0xa2/0xf0\n  [   29.584018]  create_trampoline+0x431/0x6f0\n  ...\n  [   44.343347] Kernel panic - not syncing: Attempted to kill the idle task!\n\nThe boot-time tracer is started from early_trace_init(), which runs\nbefore workqueue_init_early().  Making its trampoline read-only splits a\nlarge page, and CPA collapses it again right away.  The split table has\nbeen a kernel page table since commit 9e4a3ec3411b\n(\"x86/mm/pat: Allocate split page tables as kernel page tables\"), so the\ncollapse frees it through pagetable_free_kernel(), which queues work on\nsystem_percpu_wq - still NULL at that point.  That commit is correct in\nitself; it only lets CPA reach pagetable_free_kernel() before the\nworkqueue that function relies on exists.\n\nKeep putting the table on the list, but don\u0027t schedule the work while\nthe system is still booting.  A core_initcall schedules it once to free\nwhatever was queued by then."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-26T14:52:01.450Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/7a25ca170c12a9328f6fcf4410713beb516b01c0"
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          "url": "https://git.kernel.org/stable/c/df6c704a08bc0925d5db047b0a6221f962bda4d9"
        },
        {
          "url": "https://git.kernel.org/stable/c/2fb552b0bee70c24c092720028ab4620f5eb2646"
        }
      ],
      "title": "mm: don\u0027t schedule deferred kernel page table freeing while booting",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99093",
    "datePublished": "2026-10-26T14:52:01.450Z",
    "dateReserved": "2026-09-25T10:25:14.390Z",
    "dateUpdated": "2026-10-26T14:52:01.450Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-10-29",
      "epss": "0.00162",
      "percentile": "0.05357"
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                "programFiles": [
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: don\u0027t schedule deferred kernel page table freeing while booting\n\nBooting with a boot-time function tracer and a filter, for example\n\n  ftrace=function ftrace_filter=pud_free_pmd_page\n\npanics on 7.3-rc4 as soon as the tracer starts:\n\n  [   23.531178] Starting tracer \u0027function\u0027\n  [   23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI\n  [   23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]\n  [   23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef)\n  [   24.252248] RIP: 0010:__queue_work+0xab/0xf00\n  [   25.981629] Call Trace:\n  [   26.125727]  \u003cTASK\u003e\n  [   26.413912]  ? pagetable_free_kernel+0x20/0x120\n  [   26.990283]  queue_work_on+0x97/0xf0\n  [   27.134382]  __cpa_collapse_large_pages+0x501/0x6f0\n  [   27.566662]  cpa_flush+0x394/0x620\n  [   27.998953]  change_page_attr_set_clr+0x321/0x4a0\n  [   29.151729]  set_memory_rox+0xa2/0xf0\n  [   29.584018]  create_trampoline+0x431/0x6f0\n  ...\n  [   44.343347] Kernel panic - not syncing: Attempted to kill the idle task!\n\nThe boot-time tracer is started from early_trace_init(), which runs\nbefore workqueue_init_early().  Making its trampoline read-only splits a\nlarge page, and CPA collapses it again right away.  The split table has\nbeen a kernel page table since commit 9e4a3ec3411b\n(\"x86/mm/pat: Allocate split page tables as kernel page tables\"), so the\ncollapse frees it through pagetable_free_kernel(), which queues work on\nsystem_percpu_wq - still NULL at that point.  That commit is correct in\nitself; it only lets CPA reach pagetable_free_kernel() before the\nworkqueue that function relies on exists.\n\nKeep putting the table on the list, but don\u0027t schedule the work while\nthe system is still booting.  A core_initcall schedules it once to free\nwhatever was queued by then."
          }
        ],
        "id": "CVE-2026-99093",
        "lastModified": "2026-10-26T15:16:48.253",
        "metrics": {},
        "published": "2026-10-26T15:16:48.253",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-29T08:13:32+00:00",
      "cve": "CVE-2026-99093",
      "id": "CVE-2026-99093",
      "initial_release_date": "2026-10-26T00:00:00+00:00",
      "product_status:known_affected": "278",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm: don\u0027t schedule deferred kernel page table freeing while booting",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-99093.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-10-27T17:57:09Z",
      "cve": "CVE-2026-99093",
      "id": "CVE-2026-99093",
      "initial_release_date": "2026-10-27T00:41:29Z",
      "product_status:known_affected": "0",
      "product_status:known_not_affected": "348",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-99093",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-99093.json",
      "version": "3"
    }
  }
}



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