{
  "threat_severity" : "Low",
  "public_date" : "2025-12-30T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction",
    "id" : "2426166",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2426166"
  },
  "cvss3" : {
    "cvss3_base_score" : "3.3",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
    "status" : "verified"
  },
  "cwe" : "CWE-166",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nx86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction\nOn hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs\nwith ConfigVersion 9.3 or later support IBT in the guest. However,\ncurrent versions of Hyper-V have a bug in that there's not an ENDBR64\ninstruction at the beginning of the hypercall page. Since hypercalls are\nmade with an indirect call to the hypercall page, all hypercall attempts\nfail with an exception and Linux panics.\nA Hyper-V fix is in progress to add ENDBR64. But guard against the Linux\npanic by clearing X86_FEATURE_IBT if the hypercall page doesn't start\nwith ENDBR. The VM will boot and run without IBT.\nIf future Linux 32-bit kernels were to support IBT, additional hypercall\npage hackery would be needed to make IBT work for such kernels in a\nHyper-V VM.", "A compatibility issue was found between Linux and Hyper-V when Indirect Branch Tracking (IBT) is enabled. The Hyper-V hypercall page lacks the required ENDBR64 instruction, causing all hypercalls to fail with an exception and panic the guest." ],
  "statement" : "This affects only Hyper-V guests with IBT-capable hardware and specific VM configuration versions. The kernel fix works around the Hyper-V bug by disabling IBT when the hypercall page is incompatible, allowing the VM to boot without IBT protection.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2024-11-12T00:00:00Z",
    "advisory" : "RHSA-2024:9315",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-503.11.1.el9_5"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2024-11-12T00:00:00Z",
    "advisory" : "RHSA-2024:9315",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-503.11.1.el9_5"
  } ],
  "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" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "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-2023-54172\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-54172\nhttps://lore.kernel.org/linux-cve-announce/2025123021-CVE-2023-54172-bcdc@gregkh/T" ],
  "name" : "CVE-2023-54172",
  "csaw" : false
}