CVE-2023-53756 (GCVE-0-2023-53756)
Vulnerability from cvelistv5
Published
2025-12-08 01:19
Modified
2025-12-08 01:19
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Fix crash due to uninitialized current_vmcs KVM enables 'Enlightened VMCS' and 'Enlightened MSR Bitmap' when running as a nested hypervisor on top of Hyper-V. When MSR bitmap is updated, evmcs_touch_msr_bitmap function uses current_vmcs per-cpu variable to mark that the msr bitmap was changed. vmx_vcpu_create() modifies the msr bitmap via vmx_disable_intercept_for_msr -> vmx_msr_bitmap_l01_changed which in the end calls this function. The function checks for current_vmcs if it is null but the check is insufficient because current_vmcs is not initialized. Because of this, the code might incorrectly write to the structure pointed by current_vmcs value left by another task. Preemption is not disabled, the current task can be preempted and moved to another CPU while current_vmcs is accessed multiple times from evmcs_touch_msr_bitmap() which leads to crash. The manipulation of MSR bitmaps by callers happens only for vmcs01 so the solution is to use vmx->vmcs01.vmcs instead of current_vmcs. BUG: kernel NULL pointer dereference, address: 0000000000000338 PGD 4e1775067 P4D 0 Oops: 0002 [#1] PREEMPT SMP NOPTI ... RIP: 0010:vmx_msr_bitmap_l01_changed+0x39/0x50 [kvm_intel] ... Call Trace: vmx_disable_intercept_for_msr+0x36/0x260 [kvm_intel] vmx_vcpu_create+0xe6/0x540 [kvm_intel] kvm_arch_vcpu_create+0x1d1/0x2e0 [kvm] kvm_vm_ioctl_create_vcpu+0x178/0x430 [kvm] kvm_vm_ioctl+0x53f/0x790 [kvm] __x64_sys_ioctl+0x8a/0xc0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd
References
Impacted products
Vendor Product Version
Linux Linux Version: ceef7d10dfb6284d512c499292e6daa35ea83f90
Version: ceef7d10dfb6284d512c499292e6daa35ea83f90
Version: ceef7d10dfb6284d512c499292e6daa35ea83f90
Version: ceef7d10dfb6284d512c499292e6daa35ea83f90
Version: ceef7d10dfb6284d512c499292e6daa35ea83f90
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/vmx/hyperv.h",
            "arch/x86/kvm/vmx/vmx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/vmx/hyperv.h",
            "arch/x86/kvm/vmx/vmx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "4.18"
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            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "5.10.175",
              "versionType": "semver"
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              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.2.*",
              "status": "unaffected",
              "version": "6.2.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "versionEndExcluding": "5.10.175",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.103",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.16",
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                  "vulnerable": true
                },
                {
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              ],
              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: VMX: Fix crash due to uninitialized current_vmcs\n\nKVM enables \u0027Enlightened VMCS\u0027 and \u0027Enlightened MSR Bitmap\u0027 when running as\na nested hypervisor on top of Hyper-V. When MSR bitmap is updated,\nevmcs_touch_msr_bitmap function uses current_vmcs per-cpu variable to mark\nthat the msr bitmap was changed.\n\nvmx_vcpu_create() modifies the msr bitmap via vmx_disable_intercept_for_msr\n-\u003e vmx_msr_bitmap_l01_changed which in the end calls this function. The\nfunction checks for current_vmcs if it is null but the check is\ninsufficient because current_vmcs is not initialized. Because of this, the\ncode might incorrectly write to the structure pointed by current_vmcs value\nleft by another task. Preemption is not disabled, the current task can be\npreempted and moved to another CPU while current_vmcs is accessed multiple\ntimes from evmcs_touch_msr_bitmap() which leads to crash.\n\nThe manipulation of MSR bitmaps by callers happens only for vmcs01 so the\nsolution is to use vmx-\u003evmcs01.vmcs instead of current_vmcs.\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000338\n  PGD 4e1775067 P4D 0\n  Oops: 0002 [#1] PREEMPT SMP NOPTI\n  ...\n  RIP: 0010:vmx_msr_bitmap_l01_changed+0x39/0x50 [kvm_intel]\n  ...\n  Call Trace:\n   vmx_disable_intercept_for_msr+0x36/0x260 [kvm_intel]\n   vmx_vcpu_create+0xe6/0x540 [kvm_intel]\n   kvm_arch_vcpu_create+0x1d1/0x2e0 [kvm]\n   kvm_vm_ioctl_create_vcpu+0x178/0x430 [kvm]\n   kvm_vm_ioctl+0x53f/0x790 [kvm]\n   __x64_sys_ioctl+0x8a/0xc0\n   do_syscall_64+0x5c/0x90\n   entry_SYSCALL_64_after_hwframe+0x63/0xcd"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-08T01:19:17.081Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6baebcecf09acd19e2bab1c2911dcdba5d48a1dc"
        },
        {
          "url": "https://git.kernel.org/stable/c/6e7bc50f97c9855da83f1478f722590defd45ff2"
        },
        {
          "url": "https://git.kernel.org/stable/c/b2de2b4d4e007f9add46ea8dc06f781835e3ea9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ba95cc671c025d0d2a1c7d5e2930f0ff0980cf4"
        },
        {
          "url": "https://git.kernel.org/stable/c/93827a0a36396f2fd6368a54a020f420c8916e9b"
        }
      ],
      "title": "KVM: VMX: Fix crash due to uninitialized current_vmcs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53756",
    "datePublished": "2025-12-08T01:19:17.081Z",
    "dateReserved": "2025-12-08T01:18:04.280Z",
    "dateUpdated": "2025-12-08T01:19:17.081Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2023-53756\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-08T02:15:51.243\",\"lastModified\":\"2025-12-08T18:26:19.900\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nKVM: VMX: Fix crash due to uninitialized current_vmcs\\n\\nKVM enables \u0027Enlightened VMCS\u0027 and \u0027Enlightened MSR Bitmap\u0027 when running as\\na nested hypervisor on top of Hyper-V. When MSR bitmap is updated,\\nevmcs_touch_msr_bitmap function uses current_vmcs per-cpu variable to mark\\nthat the msr bitmap was changed.\\n\\nvmx_vcpu_create() modifies the msr bitmap via vmx_disable_intercept_for_msr\\n-\u003e vmx_msr_bitmap_l01_changed which in the end calls this function. The\\nfunction checks for current_vmcs if it is null but the check is\\ninsufficient because current_vmcs is not initialized. Because of this, the\\ncode might incorrectly write to the structure pointed by current_vmcs value\\nleft by another task. Preemption is not disabled, the current task can be\\npreempted and moved to another CPU while current_vmcs is accessed multiple\\ntimes from evmcs_touch_msr_bitmap() which leads to crash.\\n\\nThe manipulation of MSR bitmaps by callers happens only for vmcs01 so the\\nsolution is to use vmx-\u003evmcs01.vmcs instead of current_vmcs.\\n\\n  BUG: kernel NULL pointer dereference, address: 0000000000000338\\n  PGD 4e1775067 P4D 0\\n  Oops: 0002 [#1] PREEMPT SMP NOPTI\\n  ...\\n  RIP: 0010:vmx_msr_bitmap_l01_changed+0x39/0x50 [kvm_intel]\\n  ...\\n  Call Trace:\\n   vmx_disable_intercept_for_msr+0x36/0x260 [kvm_intel]\\n   vmx_vcpu_create+0xe6/0x540 [kvm_intel]\\n   kvm_arch_vcpu_create+0x1d1/0x2e0 [kvm]\\n   kvm_vm_ioctl_create_vcpu+0x178/0x430 [kvm]\\n   kvm_vm_ioctl+0x53f/0x790 [kvm]\\n   __x64_sys_ioctl+0x8a/0xc0\\n   do_syscall_64+0x5c/0x90\\n   entry_SYSCALL_64_after_hwframe+0x63/0xcd\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3ba95cc671c025d0d2a1c7d5e2930f0ff0980cf4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6baebcecf09acd19e2bab1c2911dcdba5d48a1dc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6e7bc50f97c9855da83f1478f722590defd45ff2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/93827a0a36396f2fd6368a54a020f420c8916e9b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b2de2b4d4e007f9add46ea8dc06f781835e3ea9f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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