SB2026081271 - Improper access control in Linux kernel overlayfs

Description

This security bulletin contains information about 1 vulnerability.

1) Improper access control (CVE-ID: CVE-2026-68448)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to improper access control in the overlayfs copy_file_range handling in fs/overlayfs/file.c when performing cross-superblock copy operations. A local user can invoke a copy operation between different overlayfs filesystems to disclose sensitive information.

The issue occurs because read access to the source file is checked with destination overlayfs mounter credentials instead of source overlayfs mounter credentials.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1f4a107439d2e43db176e34919933e617cb7f2c5
• https://git.kernel.org/stable/c/9ec22c8113d8cf72ed7197bb61037dcad09e50d8
• https://git.kernel.org/stable/c/a1e0eb8f55cfe09bb31a202a388babc411292656