FKIE_CVE-2026-98124

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: smb/client: invalidate fscache for fallocate range operations smb3_zero_range(), smb3_punch_hole(), smb3_insert_range(), and smb3_collapse_range() modify file contents through server-side range operations. These operations discard the affected page cache, but leave the FS-Cache cookie valid, so a later read may return data cached before the range operation. Fix this by invalidating FS-Cache after outstanding I/O has completed and before modifying the file on the server. Run the following as root on a CIFS mount with fsc enabled and an active CacheFiles backend: bash -c ' MNT=/mnt/cifs FILE="$MNT/repro" # Generate four 1 MiB random blocks: [A][B][C][D]. dd if=/dev/urandom of=/tmp/src bs=1M count=4 status=none # Expected contents after zeroing B: [A][zero][C][D]. cp /tmp/src /tmp/expected dd if=/dev/zero of=/tmp/expected bs=1M seek=1 count=1 \ conv=notrunc status=none cp /tmp/src "$FILE" # Populate FS-Cache, then discard the page cache. sync echo 1 > /proc/sys/vm/drop_caches cat "$FILE" > /dev/null sync echo 1 > /proc/sys/vm/drop_caches fallocate --zero-range -o 1M -l 1M "$FILE" if cmp -s /tmp/expected "$FILE"; then echo "readback: OK" else echo "readback: STALE DATA" fi ' Before this change, the readback differs from /tmp/expected: readback: STALE DATA After this change, it matches: readback: OK
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/448ba0ae65ca61064183564d2983c9aa59bd6ba7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/93c6e5a8d7c5071d586c1411596d5db5faad22b2
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "93c6e5a8d7c5071d586c1411596d5db5faad22b2",
              "status": "affected",
              "version": "31742c5a331766bc7df6b0d525df00c6cd20d5a6",
              "versionType": "git"
            },
            {
              "lessThan": "448ba0ae65ca61064183564d2983c9aa59bd6ba7",
              "status": "affected",
              "version": "31742c5a331766bc7df6b0d525df00c6cd20d5a6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.17"
            },
            {
              "lessThan": "3.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "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\nsmb/client: invalidate fscache for fallocate range operations\n\nsmb3_zero_range(), smb3_punch_hole(), smb3_insert_range(), and\nsmb3_collapse_range() modify file contents through server-side range\noperations. These operations discard the affected page cache, but leave\nthe FS-Cache cookie valid, so a later read may return data cached before\nthe range operation.\n\nFix this by invalidating FS-Cache after outstanding I/O has completed\nand before modifying the file on the server.\n\nRun the following as root on a CIFS mount with fsc enabled and an active\nCacheFiles backend:\n\n        bash -c \u0027\n                MNT=/mnt/cifs\n                FILE=\"$MNT/repro\"\n\n                # Generate four 1 MiB random blocks: [A][B][C][D].\n                dd if=/dev/urandom of=/tmp/src bs=1M count=4 status=none\n\n                # Expected contents after zeroing B: [A][zero][C][D].\n                cp /tmp/src /tmp/expected\n                dd if=/dev/zero of=/tmp/expected bs=1M seek=1 count=1 \\\n                        conv=notrunc status=none\n                cp /tmp/src \"$FILE\"\n\n                # Populate FS-Cache, then discard the page cache.\n                sync\n                echo 1 \u003e /proc/sys/vm/drop_caches\n                cat \"$FILE\" \u003e /dev/null\n                sync\n                echo 1 \u003e /proc/sys/vm/drop_caches\n\n                fallocate --zero-range -o 1M -l 1M \"$FILE\"\n\n                if cmp -s /tmp/expected \"$FILE\"; then\n                        echo \"readback: OK\"\n                else\n                        echo \"readback: STALE DATA\"\n                fi\n        \u0027\n\nBefore this change, the readback differs from /tmp/expected:\n\n        readback: STALE DATA\n\nAfter this change, it matches:\n\n        readback: OK"
    }
  ],
  "id": "CVE-2026-98124",
  "lastModified": "2026-09-25T11:17:43.720",
  "metrics": {},
  "published": "2026-09-25T11:17:43.720",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/448ba0ae65ca61064183564d2983c9aa59bd6ba7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/93c6e5a8d7c5071d586c1411596d5db5faad22b2"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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