{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-13T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()",
    "id" : "2457839",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2457839"
  },
  "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-369",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nnet/sched: sch_hfsc: fix divide-by-zero in rtsc_min()\nm2sm() converts a u32 slope to a u64 scaled value.  For large inputs\n(e.g. m1=4000000000), the result can reach 2^32.  rtsc_min() stores\nthe difference of two such u64 values in a u32 variable `dsm` and\nuses it as a divisor.  When the difference is exactly 2^32 the\ntruncation yields zero, causing a divide-by-zero oops in the\nconcave-curve intersection path:\nOops: divide error: 0000\nRIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601)\nCall Trace:\ninit_ed (net/sched/sch_hfsc.c:629)\nhfsc_enqueue (net/sched/sch_hfsc.c:1569)\n[...]\nWiden `dsm` to u64 and replace do_div() with div64_u64() so the full\ndifference is preserved.", "A flaw was found in the Linux kernel's Hierarchical Fair Service Curve (HFSC) network scheduler. When processing specific large input values, a calculation error can cause a variable to be truncated to zero. This zero value is then used as a divisor, leading to a divide-by-zero error and a system crash, resulting in a Denial of Service (DoS)." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "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",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "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-2026-31423\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31423\nhttps://lore.kernel.org/linux-cve-announce/2026041356-CVE-2026-31423-ed66@gregkh/T" ],
  "name" : "CVE-2026-31423",
  "csaw" : false
}