{
  "threat_severity" : "Moderate",
  "public_date" : "2025-07-19T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush",
    "id" : "2382059",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2382059"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.3",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-754",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nKVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush\nIn KVM guests with Hyper-V hypercalls enabled, the hypercalls\nHVCALL_FLUSH_VIRTUAL_ADDRESS_LIST and HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX\nallow a guest to request invalidation of portions of a virtual TLB.\nFor this, the hypercall parameter includes a list of GVAs that are supposed\nto be invalidated.\nHowever, when non-canonical GVAs are passed, there is currently no\nfiltering in place and they are eventually passed to checked invocations of\nINVVPID on Intel / INVLPGA on AMD.  While AMD's INVLPGA silently ignores\nnon-canonical addresses (effectively a no-op), Intel's INVVPID explicitly\nsignals VM-Fail and ultimately triggers the WARN_ONCE in invvpid_error():\ninvvpid failed: ext=0x0 vpid=1 gva=0xaaaaaaaaaaaaa000\nWARNING: CPU: 6 PID: 326 at arch/x86/kvm/vmx/vmx.c:482\ninvvpid_error+0x91/0xa0 [kvm_intel]\nModules linked in: kvm_intel kvm 9pnet_virtio irqbypass fuse\nCPU: 6 UID: 0 PID: 326 Comm: kvm-vm Not tainted 6.15.0 #14 PREEMPT(voluntary)\nRIP: 0010:invvpid_error+0x91/0xa0 [kvm_intel]\nCall Trace:\nvmx_flush_tlb_gva+0x320/0x490 [kvm_intel]\nkvm_hv_vcpu_flush_tlb+0x24f/0x4f0 [kvm]\nkvm_arch_vcpu_ioctl_run+0x3013/0x5810 [kvm]\nHyper-V documents that invalid GVAs (those that are beyond a partition's\nGVA space) are to be ignored.  While not completely clear whether this\nruling also applies to non-canonical GVAs, it is likely fine to make that\nassumption, and manual testing on Azure confirms \"real\" Hyper-V interprets\nthe specification in the same way.\nSkip non-canonical GVAs when processing the list of address to avoid\ntripping the INVVPID failure.  Alternatively, KVM could filter out \"bad\"\nGVAs before inserting into the FIFO, but practically speaking the only\ndownside of pushing validation to the final processing is that doing so\nis suboptimal for the guest, and no well-behaved guest will request TLB\nflushes for non-canonical addresses." ],
  "statement" : "While not a memory corruption or LPE, this is guest-triggerable denial-of-service with privileged instructions, which makes it relevant in cloud environments using nested virtualization or hosting untrusted workloads (e.g., CI systems, fuzzing infrastructure, research clusters).\nThe issue was confirmed and the fix validated by testing on Azure (which implements Hyper-V).\nA denial-of-service vulnerability was found in the KVM module of the Linux kernel when handling paravirtualized TLB flush hypercalls (HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,_EX}) under Hyper-V. On Intel hosts, passing non-canonical guest virtual addresses (GVAs) from a guest may trigger a VMFailInvalid condition during INVVPID, leading to WARN_ONCE() or kernel instability.\nPR:L is justified because the attacker must have kernel-level privileges inside the guest VM to issue the hypercall.\nS:C (scope changed) applies because the bug allows actions within a guest to impact the host kernel’s stability.\nCIA: NNH reflects that the issue does not affect confidentiality or integrity, but can significantly affect availability through a potential host crash or soft lockup.\nThe related to this bug Kernel config param CONFIG_KVM_HYPERV enabled only for the latest version of Red Hat Enterprise Linux 9.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "release_date" : "2025-10-20T00:00:00Z",
    "advisory" : "RHSA-2025:18318",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10.0",
    "package" : "kernel-0:6.12.0-55.40.1.el10_0"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2025-10-06T00:00:00Z",
    "advisory" : "RHSA-2025:17377",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-570.51.1.el9_6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2025-11-17T00:00:00Z",
    "advisory" : "RHSA-2025:21469",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-611.8.1.el9_7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2025-10-06T00:00:00Z",
    "advisory" : "RHSA-2025:17377",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-570.51.1.el9_6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2025-11-17T00:00:00Z",
    "advisory" : "RHSA-2025:21469",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-611.8.1.el9_7"
  } ],
  "package_state" : [ {
    "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" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2025-38351\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-38351\nhttps://lore.kernel.org/linux-cve-announce/2025071951-CVE-2025-38351-75ea@gregkh/T" ],
  "name" : "CVE-2025-38351",
  "mitigation" : {
    "value" : "Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.",
    "lang" : "en:us"
  },
  "csaw" : false
}