SB20260502128 - Improper Initialization in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Improper Initialization (CVE-ID: CVE-2026-31710)

CWE-ID: CWE-665 - Improper Initialization

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause incorrect path handling.

The vulnerability exists due to improper state management in cifs_mount_get_tcon() for SMB1 UNIX mounts when updating mount flags during mount processing. A local user can trigger the use of incorrect directory separators in paths to cause incorrect path handling.

The issue occurs when SMB1 UNIX mounts are used and the CIFS_MOUNT_POSIX_PATHS bit is missing from mnt_cifs_flags.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/c4d3fc5844d685441befd0caaab648321013cdfd
• https://git.kernel.org/stable/c/fbbfcf35e1ee3396631f3dc6214cb626aa9814c3