SB2026110840 - Use-after-free in Linux kernel smb server

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-99277)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to potentially cause a denial of service through a kernel use-after-free.

The vulnerability exists due to use-after-free in ksmbd session channel management when session unregistration and connection cleanup occur concurrently with access through a surviving session reference. A remote user can trigger concurrent SMB session and connection operations to potentially cause a kernel crash by accessing a channel's freed connection object.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4b333aed69cfc2c8687b86b6a4364a0dffc16dd8
• https://git.kernel.org/stable/c/add8d7fb04efe564193df73581889c62fc0016f1