CVE-2026-68428 (GCVE-0-2026-68428)
Vulnerability from cvelistv5
Published
2026-08-10 12:04
Modified
2026-08-19 16:35
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Fix use-after-free on vendor module reload
mmu_destroy_caches() destroys pte_list_desc_cache and
mmu_page_header_cache, but leaves both pointers unchanged. The pointers
live in kvm.ko, and therefore survive when a vendor module is unloaded
while kvm.ko remains loaded.
If creation of pte_list_desc_cache fails during a subsequent vendor
module load, its assignment sets pte_list_desc_cache to NULL and the
error path calls mmu_destroy_caches(). mmu_page_header_cache still
points to the cache destroyed during the preceding vendor module
unload. Passing that stale pointer to kmem_cache_destroy() causes a
slab use-after-free.
Reproduce the issue on a v7.1.3 kernel with CONFIG_KASAN=y,
CONFIG_KASAN_GENERIC=y, CONFIG_KVM=m, and CONFIG_KVM_INTEL=m. A
one-shot test hook forces pte_list_desc_cache to NULL on the second
invocation of kvm_mmu_vendor_module_init():
1. Load kvm.ko and kvm-intel.ko, creating both caches.
2. Unload only kvm_intel, leaving kvm.ko loaded.
3. Reload kvm_intel and force initialization through the -ENOMEM path.
KASAN reports:
BUG: KASAN: slab-use-after-free in
kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]
...
kmem_cache_destroy+0x21/0x1d0
kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]
...
Allocated by task 16817:
__kmem_cache_create_args+0x12c/0x3b0
__kmem_cache_create.constprop.0+0xb6/0xf0 [kvm]
kvm_mmu_vendor_module_init+0x13b/0x170 [kvm]
...
Freed by task 16820:
kmem_cache_destroy+0x117/0x1d0
kvm_mmu_vendor_module_exit+0x21/0x30 [kvm]
Clear both pointers immediately after destroying their caches so that
the stored state reflects the caches' lifetime and repeated cleanup is
safe.
With the fix applied, the same injected vendor module reload fails with
-ENOMEM as expected and produces no KASAN report.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 Version: cb498ea2ce1d3f3c0bc0a2522241dca10263e437 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/x86/kvm/mmu/mmu.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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},
{
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.25"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
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"vulnerable": true
},
{
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{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Fix use-after-free on vendor module reload\n\nmmu_destroy_caches() destroys pte_list_desc_cache and\nmmu_page_header_cache, but leaves both pointers unchanged. The pointers\nlive in kvm.ko, and therefore survive when a vendor module is unloaded\nwhile kvm.ko remains loaded.\n\nIf creation of pte_list_desc_cache fails during a subsequent vendor\nmodule load, its assignment sets pte_list_desc_cache to NULL and the\nerror path calls mmu_destroy_caches(). mmu_page_header_cache still\npoints to the cache destroyed during the preceding vendor module\nunload. Passing that stale pointer to kmem_cache_destroy() causes a\nslab use-after-free.\n\nReproduce the issue on a v7.1.3 kernel with CONFIG_KASAN=y,\nCONFIG_KASAN_GENERIC=y, CONFIG_KVM=m, and CONFIG_KVM_INTEL=m. A\none-shot test hook forces pte_list_desc_cache to NULL on the second\ninvocation of kvm_mmu_vendor_module_init():\n\n 1. Load kvm.ko and kvm-intel.ko, creating both caches.\n 2. Unload only kvm_intel, leaving kvm.ko loaded.\n 3. Reload kvm_intel and force initialization through the -ENOMEM path.\n\nKASAN reports:\n\n BUG: KASAN: slab-use-after-free in\n kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]\n ...\n kmem_cache_destroy+0x21/0x1d0\n kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]\n ...\n Allocated by task 16817:\n __kmem_cache_create_args+0x12c/0x3b0\n __kmem_cache_create.constprop.0+0xb6/0xf0 [kvm]\n kvm_mmu_vendor_module_init+0x13b/0x170 [kvm]\n ...\n Freed by task 16820:\n kmem_cache_destroy+0x117/0x1d0\n kvm_mmu_vendor_module_exit+0x21/0x30 [kvm]\n\nClear both pointers immediately after destroying their caches so that\nthe stored state reflects the caches\u0027 lifetime and repeated cleanup is\nsafe.\n\nWith the fix applied, the same injected vendor module reload fails with\n-ENOMEM as expected and produces no KASAN report."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:35:25.214Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/034b7fa1f5846d69eb51f12ce6d1c71871e83c2d"
},
{
"url": "https://git.kernel.org/stable/c/42272b0f239f3a89f9c26a01cc37aee06138b1b7"
},
{
"url": "https://git.kernel.org/stable/c/940950d5cd86f250dca578279ad5ca63b4e0986b"
},
{
"url": "https://git.kernel.org/stable/c/6f4be73880302d5642c83a0813fdfe1f5fd4b6e3"
},
{
"url": "https://git.kernel.org/stable/c/32b9f89ed9e6d7a45075d64089c254a7f6e13695"
},
{
"url": "https://git.kernel.org/stable/c/ec9daa8fd1b6f45545c9839dca55bd867fad9e13"
},
{
"url": "https://git.kernel.org/stable/c/43cfb20d62ffe49626d62beecfc32eb6f262191c"
},
{
"url": "https://git.kernel.org/stable/c/52f2f7c30126037975389aa04d24c506a5177c35"
}
],
"title": "KVM: x86/mmu: Fix use-after-free on vendor module reload",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68428",
"datePublished": "2026-08-10T12:04:48.905Z",
"dateReserved": "2026-07-30T09:28:09.393Z",
"dateUpdated": "2026-08-19T16:35:25.214Z",
"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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