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CVE-2026-89760

Estado: RecibidaAlta (7.8)—

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

mm, swap: don't free a hibernation slot that is in the swap cache

A slot with a folio in the swap cache is freed when the folio leaves the cache, not when its count drops. swap_put_entries_cluster() follows that rule. swap_free_hibernation_slot() does not, it calls __swap_cluster_free_entries() whether or not a folio sits on the slot.

Cluster readahead can put one there. It walks a raw page_cluster sized window of offsets around the faulting entry, and a hibernation slot passes __swap_cache_add_check() because it is not a folio and its count is not zero. Freeing the slot then clears the entry under that folio.

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The folio is now unreachable from the swap table, and the offset goes back to the allocator. The folio is still on the LRU though, so reclaim can pick it up later. It then takes the old offset out of folio->swap and overwrites the table entry there, which by then may belong to someone else.

This bug can trigger silent memory corruption, process crashes, or data instability across completely unrelated userspace applications - typically occurring when uswsusp is preparing the hibernation image.

I found this while working on giving hibernation slots their own marker in the swap table, which I had discussed with Kairui. (https://lore.kernel.org/linux-mm/abp7aDgYLrxF3Me8@KASONG-MC4/) As far as I know there are no reports, so there is no Reported-by/Closes to add.

Check for a cached folio before freeing. The slot is then left in the ordinary state where only the swap cache holds it, and it is freed when the folio leaves the cache, either through the reclaim below or through normal reclaim later.

CVSS

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad en kernel Linux con AV:L/PR:L (acceso local con privilegios) que causa corrupción de memoria silenciosa y crashes. Un usuario local puede manipular asignaciones de swap para sobrescribir entradas de tabla, afectando procesos no relacionados.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramRestrict File and Directory PermissionsRemote Data StorageFilter Network TrafficExecution PreventionEncrypt Sensitive Information

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)

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{
  "id": "CVE-2026-89760",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "0d6af9bcf383bcdf601e670bb605861b01e318e7",
              "lessThan": "a6df73156f2d85746c69adbf13d0f5ea200e0626",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0d6af9bcf383bcdf601e670bb605861b01e318e7",
              "lessThan": "10d9012e83efedde8718ceaa5053f836e0c8596c",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "mm/swapfile.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "mm/swapfile.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:20:07.120",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/10d9012e83efedde8718ceaa5053f836e0c8596c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a6df73156f2d85746c69adbf13d0f5ea200e0626",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm, swap: don't free a hibernation slot that is in the swap cache\n\nA slot with a folio in the swap cache is freed when the folio leaves the\ncache, not when its count drops.  swap_put_entries_cluster() follows that\nrule.  swap_free_hibernation_slot() does not, it calls\n__swap_cluster_free_entries() whether or not a folio sits on the slot.\n\nCluster readahead can put one there.  It walks a raw page_cluster sized\nwindow of offsets around the faulting entry, and a hibernation slot passes\n__swap_cache_add_check() because it is not a folio and its count is not\nzero.  Freeing the slot then clears the entry under that folio.\n\nThe folio is now unreachable from the swap table, and the offset goes back\nto the allocator.  The folio is still on the LRU though, so reclaim can\npick it up later.  It then takes the old offset out of folio->swap and\noverwrites the table entry there, which by then may belong to someone\nelse.\n\nThis bug can trigger silent memory corruption, process crashes, or data\ninstability across completely unrelated userspace applications - typically\noccurring when uswsusp is preparing the hibernation image.\n\nI found this while working on giving hibernation slots their own marker in\nthe swap table, which I had discussed with Kairui. \n(https://lore.kernel.org/linux-mm/abp7aDgYLrxF3Me8@KASONG-MC4/) As far as\nI know there are no reports, so there is no Reported-by/Closes to add.\n\nCheck for a cached folio before freeing.  The slot is then left in the\nordinary state where only the swap cache holds it, and it is freed when\nthe folio leaves the cache, either through the reclaim below or through\nnormal reclaim later."
    }
  ],
  "lastModified": "2026-09-13T07:17:40.307",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}