FKIE_CVE-2026-68448

Vulnerability from fkie_nvd - Published: 2026-08-12 01:17 - Updated: 2026-08-17 06:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ovl: check access to copy_file_range source with src mounter creds Commit 5dae222a5ff0c ("vfs: allow copy_file_range to copy across devices") allowed filesystems that implement the copy_file_range() f_op to decide if they want to access cross-sb copy from/to the same fs type. The same commit added checks to verify same sb copy for filesystems that implement ->copy_file_range() and do not support cross-sb copy at the time, namely, to ceph, fuse and nfs. The two remaining fs which implement ->copy_file_range(), cifs and overlayfs started to support cross-sb copy from this time. While overlayfs does support cross-sb copy when the two underlying files are on the same base fs, the copy operation on the two real files from two different overalyfs filesystems is performed with the mounter creds of the destination overlayfs and the read permission access hook for the source file was called with the wrong creds. This could cause either deny of access to copy which would otherwise be allowed (e.g. with splice) or allow read access to file which would otherwise be denied. Fix the latter case by explicitly verifying read access to source file with the source overlayfs mounter creds. The former case remains a quirk of cross-sb overlayfs copy, but userspace could fall back to regular copy so no harm done.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1f4a107439d2e43db176e34919933e617cb7f2c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9ec22c8113d8cf72ed7197bb61037dcad09e50d8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a1e0eb8f55cfe09bb31a202a388babc411292656
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/overlayfs/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9ec22c8113d8cf72ed7197bb61037dcad09e50d8",
              "status": "affected",
              "version": "5dae222a5ff0c269730393018a5539cc970a4726",
              "versionType": "git"
            },
            {
              "lessThan": "1f4a107439d2e43db176e34919933e617cb7f2c5",
              "status": "affected",
              "version": "5dae222a5ff0c269730393018a5539cc970a4726",
              "versionType": "git"
            },
            {
              "lessThan": "a1e0eb8f55cfe09bb31a202a388babc411292656",
              "status": "affected",
              "version": "5dae222a5ff0c269730393018a5539cc970a4726",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/overlayfs/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\novl: check access to copy_file_range source with src mounter creds\n\nCommit 5dae222a5ff0c (\"vfs: allow copy_file_range to copy across devices\")\nallowed filesystems that implement the copy_file_range() f_op to decide\nif they want to access cross-sb copy from/to the same fs type.\n\nThe same commit added checks to verify same sb copy for filesystems that\nimplement -\u003ecopy_file_range() and do not support cross-sb copy at the\ntime, namely, to ceph, fuse and nfs.\n\nThe two remaining fs which implement -\u003ecopy_file_range(), cifs and\noverlayfs started to support cross-sb copy from this time.\n\nWhile overlayfs does support cross-sb copy when the two underlying files\nare on the same base fs, the copy operation on the two real files from\ntwo different overalyfs filesystems is performed with the mounter\ncreds of the destination overlayfs and the read permission access hook\nfor the source file was called with the wrong creds.\n\nThis could cause either deny of access to copy which would otherwise be\nallowed (e.g. with splice) or allow read access to file which would\notherwise be denied.\n\nFix the latter case by explicitly verifying read access to source file\nwith the source overlayfs mounter creds.\n\nThe former case remains a quirk of cross-sb overlayfs copy, but\nuserspace could fall back to regular copy so no harm done."
    }
  ],
  "id": "CVE-2026-68448",
  "lastModified": "2026-08-17T06:17:53.900",
  "metrics": {},
  "published": "2026-08-12T01:17:07.697",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1f4a107439d2e43db176e34919933e617cb7f2c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9ec22c8113d8cf72ed7197bb61037dcad09e50d8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a1e0eb8f55cfe09bb31a202a388babc411292656"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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