{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64458",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-64458"
  ],
  "published": "2026-07-25T08:51:45Z",
  "summary": "mm/damon/ops-common: handle extreme intervals in damon_hot_score()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/ops-common: handle extreme intervals in damon_hot_score()\n\nFix three issues in damon_hot_score() that comes from wrong handling of\nextreme (zero or too high) monitoring intervals user setup.\n\nWhen the user sets sampling interval zero, damon_max_nr_accesses(), which\nis called from damon_hot_score(), causes a divide-by-zero.  Needless to\nsay, it is a problem.\n\nWhen the user sets the aggregation interval zero, the function returns\nzero.  It is wrong, since the real maximum nr_acceses in the setup should\nbe one.  Worse yet, it can cause another divide-by-zero from its caller,\ndamon_hot_score(), since it uses damon_max_nr_accesses() return value as a\ndenominator.\n\nWhen the user sets the aggregation interval very high, damon_hot_score()\ncould return a value out of [0, DAMOS_MAX_SCORE] range.  Since the return\nvalue is used as an index to the regions_score_histogram array, which is\nDAMOS_MAX_SCORE+1 size, it causes out of bounds array access.\n\nThe issues can be relatively easily reproduced like below.  The sysfs\nwrite permission is required, though.\n\n    # ./damo start --damos_action lru_prio --damos_quota_space 100M \\\n            --damos_quota_interval 1s\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/0/monitoring_attrs/intervals/sample_us\n    # echo 0 > contexts/0/monitoring_attrs/intervals/aggr_us\n    # echo commit > state\n    # dmesg\n    [...]\n    [  131.329762] Oops: divide error: 0000 [#1] SMP NOPTI\n    [...]\n    [  131.336089] RIP: 0010:damon_hot_score+0x27/0xd0\n    [...]\n\nFix the divide-by-zero intervals problems by explicitly handling the zero\nintervals in damon_max_nr_accesses().  Fix the out-of-bound array access\nby applying [0, DAMOS_MAX_SCORE] bounds before returning from\ndamon_hot_score().\n\nThe issue was discovered [1] by Sashiko.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.178",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64458"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/58321b4e6e4f0f412069ab27ccdd56292757343a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/74fef68d521150281e36cdaa20e9e1ee3e3aa146"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ef2ae10a4582bc92b7e944181bbd2f87f3d30f3a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9c8f31eaae6140ecadec0c07320498a944556de2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/76e415ea88d20f022ed5cfcf78c50e156a267e91"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/35d4a3cf70a855b50e53189ac2f8463e20a02046"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-17T05:24:08Z"
  }
}