{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "671e266835b8a87d6cc2c6db962de23783405dd8"
            },
            {
              "fixed": "51fe3fe0ffec033bd831c71d9bee3dee827e491c"
            },
            {
              "fixed": "08988d1941e180f0ad30d91233cb64f3418ba23c"
            },
            {
              "fixed": "777dbc9914b2f003f1d44af80c7a4a395c5961b2"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.18.0"
            },
            {
              "fixed": "6.18.52"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90100.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nptp: netc: fix period truncation and potential divide-by-zero in PEROUT\n\nThe max_period bound in net_timer_enable_perout() was computed as:\n\n  max_period = (u64)NETC_TMR_DEFAULT_FIPER + integral_period;\n\nwhich exceeds U32_MAX when integral_period \u003e 0 (e.g. 0x100000002 for\nthe default 333333333 Hz clock). A period_ns that passes this check but\nexceeds U32_MAX is then silently truncated when stored into the u32\nstruct netc_pp::period field.\n\nA truncated value of zero can reach netc_timer_set_perout_alarm(), where\nthe local u32 period variable would also be 0, causing a divide-by-zero\nin roundup_u64(delta, period) whenever the stime \u003c min_time branch is\ntaken (which always happens for a start time of {0, 0}).\n\nAdditionally, netc_timer_enable_periodic_pulse() and\nnetc_timer_enable_fiper() both compute:\n\n  fiper = pp-\u003eperiod - integral_period;\n\nA zero pp-\u003eperiod results in an unsigned wraparound to 0xFFFFFFFD,\nmis-programming the FIPER hardware register.\n\nFix all three issues by capping max_period at NETC_TMR_DEFAULT_FIPER\n(0xFFFFFFFF). This ensures that any period_ns passing the range check\nfits in a u32 without truncation, so the stored value is always valid\nand non-zero. The accepted range is reduced by integral_period ns\n(typically only a few nanoseconds), which is negligible in practice.",
  "id": "CVE-2026-90100",
  "modified": "2026-09-19T03:30:46.582530911Z",
  "published": "2026-09-17T16:06:11.515Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08988d1941e180f0ad30d91233cb64f3418ba23c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/51fe3fe0ffec033bd831c71d9bee3dee827e491c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/777dbc9914b2f003f1d44af80c7a4a395c5961b2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90100.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90100"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ptp: netc: fix period truncation and potential divide-by-zero in PEROUT"
}