« Volver al listado

CVE-2026-74645

Estado: RecibidaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

mm/damon/lru_sort: error out for >10000 active_mem_bp

damos_quota_score() can trigger division by zero if the target value is zero. DAMON_LRU_SORT lets users set the target value for the hot memory scheme via active_mem_bp parameter. It avoids setting it as the target value if the parameter value is zero. However, it also sets the cold memory scheme with a target value that is calculated as '10000 - active_mem_bp + 2'. Hence, if a user sets active_mem_bp 10002, the cold memory scheme's quota goal target value can be zero. As a result, division by zero can be triggered. Fix by returning an error when the user tries to start DAMON with >10000 active_mem_bp parameter value.

Leer descripción completaMostrar menos

It makes no sense to set active_mem_bp with 10002. It also requires module parameters write permission to reproduce the issue. That said, the consequence is quite bad.

One reliable way to reproduce the issue is like below:

This issue was discovered [1] by Sashiko.

Detalles técnicos trazas, registros y código del informe original
    # cd /sys/module/damon_lru_sort/parameters
    # echo 1000 > wmarks_high
    # echo 995 > wmarks_mid
    # echo 0 > wmarks_low
    # echo 10002 > active_mem_bp
    # echo Y > enabled
    # dmesg -w
    [...]
    [  597.421247] Oops: divide error: 0000 [#1] SMP NOPTI
    [  597.428848] RIP: 0010:damos_quota_score+0x6f/0x480

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-74645",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "40d98d31cd7060228e03303c5c34ae7101020416",
              "lessThan": "e7e5e5e0dfe2ea171044c24c263efae4ee882b3f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "40d98d31cd7060228e03303c5c34ae7101020416",
              "lessThan": "06befa61c427e74319781e6f35a364cfc32dbae8",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "mm/damon/lru_sort.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "mm/damon/lru_sort.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-22T16:16:37.837",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/06befa61c427e74319781e6f35a364cfc32dbae8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e7e5e5e0dfe2ea171044c24c263efae4ee882b3f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/lru_sort: error out for >10000 active_mem_bp\n\ndamos_quota_score() can trigger division by zero if the target value is\nzero.  DAMON_LRU_SORT lets users set the target value for the hot memory\nscheme via active_mem_bp parameter.  It avoids setting it as the target\nvalue if the parameter value is zero.  However, it also sets the cold\nmemory scheme with a target value that is calculated as '10000 -\nactive_mem_bp + 2'.  Hence, if a user sets active_mem_bp 10002, the cold\nmemory scheme's quota goal target value can be zero.  As a result,\ndivision by zero can be triggered.  Fix by returning an error when the\nuser tries to start DAMON with >10000 active_mem_bp parameter value.\n\nIt makes no sense to set active_mem_bp with 10002.  It also requires\nmodule parameters write permission to reproduce the issue.  That said, the\nconsequence is quite bad.\n\nOne reliable way to reproduce the issue is like below:\n\n    # cd /sys/module/damon_lru_sort/parameters\n    # echo 1000 > wmarks_high\n    # echo 995 > wmarks_mid\n    # echo 0 > wmarks_low\n    # echo 10002 > active_mem_bp\n    # echo Y > enabled\n    # dmesg -w\n    [...]\n    [  597.421247] Oops: divide error: 0000 [#1] SMP NOPTI\n    [  597.428848] RIP: 0010:damos_quota_score+0x6f/0x480\n\nThis issue was discovered [1] by Sashiko."
    }
  ],
  "lastModified": "2026-08-22T16:16:37.837",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}