CVE Catalog

CVE-2026-68448

Low risk· EPSS 5%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.16%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel, the overlayfs filesystem has a vulnerability related to incorrect access checks for the source file during copy_file_range operations. The copy operation between two overlayfs is performed with the mounter creds of the destination overlayfs, not the source, which may lead to unauthorized file access or denial of access. The fix adds an explicit read access check to the source file with the source overlayfs mounter creds.

Risk Assessment

The vulnerability may allow unauthorized file reads or block legitimate copy operations, compromising data integrity and confidentiality.

Recommendation

It is recommended to update the Linux kernel to a version containing the fix that checks source access with appropriate credentials.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS