{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-24T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION",
    "id" : "2461540",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2461540"
  },
  "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" : "draft"
  },
  "cwe" : "CWE-190",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nKVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION\nDrop the WARN in sev_pin_memory() on npages overflowing an int, as the\nWARN is comically trivially to trigger from userspace, e.g. by doing:\nstruct kvm_enc_region range = {\n.addr = 0,\n.size = -1ul,\n};\n__vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range);\nNote, the checks in sev_mem_enc_register_region() that presumably exist to\nverify the incoming address+size are completely worthless, as both \"addr\"\nand \"size\" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater\nthan ULONG_MAX.  That wart will be cleaned up in the near future.\nif (range->addr > ULONG_MAX || range->size > ULONG_MAX)\nreturn -EINVAL;\nOpportunistically add a comment to explain why the code calculates the\nnumber of pages the \"hard\" way, e.g. instead of just shifting @ulen.", "A flaw was found in the Linux kernel, specifically within the Kernel-based Virtual Machine (KVM) subsystem's Secure Encrypted Virtualization (SEV) feature. A local user could exploit this vulnerability by providing an excessively large memory region size when using the KVM_MEMORY_ENCRYPT_REG_REGION command. This action could trigger a kernel warning, potentially leading to system instability or consuming excessive system resources. The primary impact of this flaw is a Denial of Service (DoS), where legitimate system operations could be disrupted." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "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",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "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-2026-31590\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31590\nhttps://lore.kernel.org/linux-cve-announce/2026042414-CVE-2026-31590-a7e3@gregkh/T" ],
  "name" : "CVE-2026-31590",
  "csaw" : false
}