CVE-2026-99093 (GCVE-0-2026-99093)
Vulnerability from cvelistv5
Published
2026-10-26 14:52
Modified
2026-10-26 14:52
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/pgtable-generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "7a25ca170c12a9328f6fcf4410713beb516b01c0",
"status": "affected",
"version": "84e0cd79d57f06b872154eb5d8f610584133f260",
"versionType": "git"
},
{
"lessThan": "df6c704a08bc0925d5db047b0a6221f962bda4d9",
"status": "affected",
"version": "922873cf4fc34124215070a8ad391bf831538bb9",
"versionType": "git"
},
{
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"status": "affected",
"version": "9e4a3ec3411bb6bb59e3c1f29b75609f1e87aac4",
"versionType": "git"
}
]
},
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/pgtable-generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "6.18.57",
"status": "affected",
"version": "6.18.53",
"versionType": "semver"
},
{
"lessThan": "7.2.11",
"status": "affected",
"version": "7.2.7",
"versionType": "semver"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.57",
"versionStartIncluding": "6.18.53",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.11",
"versionStartIncluding": "7.2.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-26T14:52:01.450Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/7a25ca170c12a9328f6fcf4410713beb516b01c0"
},
{
"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",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"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"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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