{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-24T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: mm/userfaultfd: fix hugetlb fault mutex hash calculation",
    "id" : "2461557",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2461557"
  },
  "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-821",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nmm/userfaultfd: fix hugetlb fault mutex hash calculation\nIn mfill_atomic_hugetlb(), linear_page_index() is used to calculate the\npage index for hugetlb_fault_mutex_hash().  However, linear_page_index()\nreturns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash()\nexpects the index in huge page units.  This mismatch means that different\naddresses within the same huge page can produce different hash values,\nleading to the use of different mutexes for the same huge page.  This can\ncause races between faulting threads, which can corrupt the reservation\nmap and trigger the BUG_ON in resv_map_release().\nFix this by introducing hugetlb_linear_page_index(), which returns the\npage index in huge page granularity, and using it in place of\nlinear_page_index().", "A flaw was found in the Linux kernel. A mismatch in the calculation of page indexes for huge pages within the `mm/userfaultfd` component can lead to race conditions between threads. These race conditions can corrupt the reservation map, potentially causing a system crash and resulting in a Denial of Service (DoS)." ],
  "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" : "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",
    "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-2026-31575\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31575\nhttps://lore.kernel.org/linux-cve-announce/2026042409-CVE-2026-31575-c1bf@gregkh/T" ],
  "name" : "CVE-2026-31575",
  "csaw" : false
}