SB20260928374 - Memory leak in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Memory leak (CVE-ID: CVE-2026-97556)

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

CVSSv4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a missing reference count release in cifs_oplock_break() in the SMB client when handling an oplock break after cifs_sb_tlink() fails. A local user can trigger an oplock break that encounters a cifs_sb_tlink() failure to cause a denial of service.

Only SMB mounts using the multiuser option are affected.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
• https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71
• https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693
• https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d