FKIE_CVE-2026-68428

Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-19 17:20
Severity
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/034b7fa1f5846d69eb51f12ce6d1c71871e83c2d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32b9f89ed9e6d7a45075d64089c254a7f6e13695
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/42272b0f239f3a89f9c26a01cc37aee06138b1b7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/43cfb20d62ffe49626d62beecfc32eb6f262191c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/52f2f7c30126037975389aa04d24c506a5177c35
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6f4be73880302d5642c83a0813fdfe1f5fd4b6e3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/940950d5cd86f250dca578279ad5ca63b4e0986b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ec9daa8fd1b6f45545c9839dca55bd867fad9e13
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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": [
            {
              "lessThan": "034b7fa1f5846d69eb51f12ce6d1c71871e83c2d",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "42272b0f239f3a89f9c26a01cc37aee06138b1b7",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "940950d5cd86f250dca578279ad5ca63b4e0986b",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "6f4be73880302d5642c83a0813fdfe1f5fd4b6e3",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "32b9f89ed9e6d7a45075d64089c254a7f6e13695",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "ec9daa8fd1b6f45545c9839dca55bd867fad9e13",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "43cfb20d62ffe49626d62beecfc32eb6f262191c",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            },
            {
              "lessThan": "52f2f7c30126037975389aa04d24c506a5177c35",
              "status": "affected",
              "version": "cb498ea2ce1d3f3c0bc0a2522241dca10263e437",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "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": [
            {
              "status": "affected",
              "version": "2.6.25"
            },
            {
              "lessThan": "2.6.25",
              "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"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-68428",
  "lastModified": "2026-08-19T17:20:49.760",
  "metrics": {},
  "published": "2026-08-10T13:20:36.770",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/034b7fa1f5846d69eb51f12ce6d1c71871e83c2d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/32b9f89ed9e6d7a45075d64089c254a7f6e13695"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/42272b0f239f3a89f9c26a01cc37aee06138b1b7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/43cfb20d62ffe49626d62beecfc32eb6f262191c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/52f2f7c30126037975389aa04d24c506a5177c35"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6f4be73880302d5642c83a0813fdfe1f5fd4b6e3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/940950d5cd86f250dca578279ad5ca63b4e0986b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ec9daa8fd1b6f45545c9839dca55bd867fad9e13"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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