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CVE-2026-89490

Estado: RecibidaSin puntuar—

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

ocfs2: fix readdir position truncation on 32-bit kernels

In ocfs2_dir_foreach_blk_el(), the directory cookie position is rebuilt with

`ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is unsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask

is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB block size). In the AND expression with the 64-bit `ctx->pos`, that unsigned operand is zero-extended to 64 bits per the usual arithmetic conversions, yielding 0x00000000fffff000. The high 32 bits of `ctx->pos` are silently cleared, even though directory size is allowed to exceed 4 GiB.

Leer descripción completaMostrar menos

When readdir() crosses the 4 GiB boundary on a 32-bit kernel the position is reset back into the first 4 GiB block, making the re-validation path re-enumerate already-returned dirents indefinitely.

This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken for all non-inline directories, so a directory large enough to cross 4 GiB reaches it.

This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix bitwise operation having different size") fixed in exfat, and the fix mirrors the equivalent ext4 fix in this series. Cast the operand to loff_t so the mask is 64-bit before the AND:

64-bit kernels are unaffected.

Detalles técnicos trazas, registros y código del informe original
	ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset;

	~(sb->s_blocksize - 1)

	ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset;

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-2026-89490",
  "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": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "c28dc3407937aa8f225942538cd585c9b28ea65a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "94569154ba49f5f85645d2019c8e206213d8404e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "1ae7029823ae4c91664cb32eec7fb8dd5e1a337a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "f9dd5cad8d09110ddff2db1fe756aae93c7552ff",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "1001fb3b69a11eaa0dc7c7428f6edfa48b88997a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "lessThan": "c0c165487a2ea5a37ddcdab4259157b7a527129c",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "versionType": "git"
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              "lessThan": "a63308ab426f3a3c7e33b02c150ea59054620261",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/ocfs2/dir.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ocfs2/dir.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:30.810",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1001fb3b69a11eaa0dc7c7428f6edfa48b88997a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1ae7029823ae4c91664cb32eec7fb8dd5e1a337a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/94569154ba49f5f85645d2019c8e206213d8404e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a63308ab426f3a3c7e33b02c150ea59054620261",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b53e2b271eeb6040c2a4a78230c570dc41cdcfa4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c0c165487a2ea5a37ddcdab4259157b7a527129c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c28dc3407937aa8f225942538cd585c9b28ea65a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f9dd5cad8d09110ddff2db1fe756aae93c7552ff",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix readdir position truncation on 32-bit kernels\n\nIn ocfs2_dir_foreach_blk_el(), the directory cookie position is\nrebuilt with\n\n\tctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset;\n\n`ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is\nunsigned long.  On 32-bit kernels unsigned long is 32-bit, so the mask\n\n\t~(sb->s_blocksize - 1)\n\nis computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB\nblock size).  In the AND expression with the 64-bit `ctx->pos`, that\nunsigned operand is zero-extended to 64 bits per the usual arithmetic\nconversions, yielding 0x00000000fffff000.  The high 32 bits of\n`ctx->pos` are silently cleared, even though directory size is\nallowed to exceed 4 GiB.\n\nWhen readdir() crosses the 4 GiB boundary on a 32-bit kernel the\nposition is reset back into the first 4 GiB block, making the\nre-validation path re-enumerate already-returned dirents indefinitely.\n\nThis is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken\nfor all non-inline directories, so a directory large enough to cross\n4 GiB reaches it.\n\nThis is the same class of bug that commit 3dce5bb82c97 (\"exfat: Fix\nbitwise operation having different size\") fixed in exfat, and the\nfix mirrors the equivalent ext4 fix in this series.  Cast the operand\nto loff_t so the mask is 64-bit before the AND:\n\n\tctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset;\n\n64-bit kernels are unaffected."
    }
  ],
  "lastModified": "2026-09-14T13:19:05.950",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}