FKIE_CVE-2026-64159

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-19 16:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix zeropoint update where i_size > remote_i_size Fix the update of the zero point[*] by netfs_release_folio() when there is uncommitted data in the pagecache beyond the folio being released but the on-server EOF is in this folio (ie. i_size > remote_i_size). The update needs to limit zero_point to remote_i_size, not i_size as i_size is a local phenomenon reflecting updates made locally to the pagecache, not stuff written to the server. remote_i_size tracks the server's i_size. [*] The zero point is the file position from which we can assume that the server will just return zeros, so we can avoid generating reads. Note that netfs_invalidate_folio() probably doesn't need fixing as zero_point should be updated by setattr after truncation or fallocate. Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \ /xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0x1bbae 0x82864 write 0x3ef2e 0xf9c8 0x1bbae write 0x67e05 0xcb5a 0x4e8f6 mapread 0x57781 0x85b6 0x7495f copy_range 0x5d3d 0x10329 0x54fac 0x7495f write 0x64710 0x1c2b 0x7495f mapread 0x64000 0x1000 0x7495f on cifs with the default cache option. It shows read-gaps on folio 0x64 failing with a short read (ie. it hits EOF) if the FMODE_READ check is commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx)) { and no fscache. This was initially found with the generic/522 xfstest.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4543a4d737944134a1394afe797622546fbcc98a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5cd5207de519ef0c085f4f559adf5eefcb4c5202
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5cd5207de519ef0c085f4f559adf5eefcb4c5202",
              "status": "affected",
              "version": "cce6bfa6ca0e30af9927b0074c97fe6a92f28092",
              "versionType": "git"
            },
            {
              "lessThan": "4543a4d737944134a1394afe797622546fbcc98a",
              "status": "affected",
              "version": "cce6bfa6ca0e30af9927b0074c97fe6a92f28092",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e2814004138a541110d4b2dc254a8f619c2c4ce0",
              "versionType": "git"
            },
            {
              "lessThan": "6.11",
              "status": "affected",
              "version": "6.10.8",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix zeropoint update where i_size \u003e remote_i_size\n\nFix the update of the zero point[*] by netfs_release_folio() when there is\nuncommitted data in the pagecache beyond the folio being released but the\non-server EOF is in this folio (ie. i_size \u003e remote_i_size).  The update\nneeds to limit zero_point to remote_i_size, not i_size as i_size is a local\nphenomenon reflecting updates made locally to the pagecache, not stuff\nwritten to the server.  remote_i_size tracks the server\u0027s i_size.\n\n[*] The zero point is the file position from which we can assume that the\n    server will just return zeros, so we can avoid generating reads.\n\nNote that netfs_invalidate_folio() probably doesn\u0027t need fixing as\nzero_point should be updated by setattr after truncation or fallocate.\n\nFound with:\n\n    fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \\\n        /xfstest.test/junk --replay-ops=junk.fsxops\n\nusing the following as junk.fsxops:\n\n    truncate 0x0 0x1bbae 0x82864\n    write 0x3ef2e 0xf9c8 0x1bbae\n    write 0x67e05 0xcb5a 0x4e8f6\n    mapread 0x57781 0x85b6 0x7495f\n    copy_range 0x5d3d 0x10329 0x54fac 0x7495f\n    write 0x64710 0x1c2b 0x7495f\n    mapread 0x64000 0x1000 0x7495f\n\non cifs with the default cache option.\n\nIt shows read-gaps on folio 0x64 failing with a short read (ie. it hits\nEOF) if the FMODE_READ check is commented out in netfs_perform_write():\n\n                if (//(file-\u003ef_mode \u0026 FMODE_READ) ||\n                    netfs_is_cache_enabled(ctx)) {\n\nand no fscache.  This was initially found with the generic/522 xfstest."
    }
  ],
  "id": "CVE-2026-64159",
  "lastModified": "2026-07-19T16:17:57.913",
  "metrics": {},
  "published": "2026-07-19T16:17:57.913",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4543a4d737944134a1394afe797622546fbcc98a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5cd5207de519ef0c085f4f559adf5eefcb4c5202"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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