{
  "threat_severity" : "Moderate",
  "public_date" : "2025-12-08T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: KVM: VMX: Fix crash due to uninitialized current_vmcs",
    "id" : "2419865",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2419865"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-824",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nKVM: VMX: Fix crash due to uninitialized current_vmcs\nKVM enables 'Enlightened VMCS' and 'Enlightened MSR Bitmap' 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.\nvmx_vcpu_create() modifies the msr bitmap via vmx_disable_intercept_for_msr\n-> 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.\nThe manipulation of MSR bitmaps by callers happens only for vmcs01 so the\nsolution is to use vmx->vmcs01.vmcs instead of current_vmcs.\nBUG: kernel NULL pointer dereference, address: 0000000000000338\nPGD 4e1775067 P4D 0\nOops: 0002 [#1] PREEMPT SMP NOPTI\n...\nRIP: 0010:vmx_msr_bitmap_l01_changed+0x39/0x50 [kvm_intel]\n...\nCall Trace:\nvmx_disable_intercept_for_msr+0x36/0x260 [kvm_intel]\nvmx_vcpu_create+0xe6/0x540 [kvm_intel]\nkvm_arch_vcpu_create+0x1d1/0x2e0 [kvm]\nkvm_vm_ioctl_create_vcpu+0x178/0x430 [kvm]\nkvm_vm_ioctl+0x53f/0x790 [kvm]\n__x64_sys_ioctl+0x8a/0xc0\ndo_syscall_64+0x5c/0x90\nentry_SYSCALL_64_after_hwframe+0x63/0xcd" ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-11-07T00:00:00Z",
    "advisory" : "RHSA-2023:6583",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-362.8.1.el9_3"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-11-07T00:00:00Z",
    "advisory" : "RHSA-2023:6583",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-362.8.1.el9_3"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9.0 Extended Update Support",
    "release_date" : "2023-06-06T00:00:00Z",
    "advisory" : "RHSA-2023:3465",
    "cpe" : "cpe:/a:redhat:rhel_eus:9.0",
    "package" : "kernel-0:5.14.0-70.58.1.el9_0"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2023-53756\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53756\nhttps://lore.kernel.org/linux-cve-announce/2025120843-CVE-2023-53756-f234@gregkh/T" ],
  "name" : "CVE-2023-53756",
  "csaw" : false
}