SB20260912143 - Use-after-free in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-89637)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory leaks and use-after-free conditions.

The vulnerability exists due to use-after-free in the SMB client cifs_check_trans2() function when processing a malformed secondary TRANSACT2 response. A remote attacker can send a malformed secondary TRANSACT2 response to cause memory leaks and use-after-free conditions.

Exploitation requires that a valid primary TRANSACT2 response has already been received.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/5e6533a683f6a851158d9f33fb4ea8f4f25d7f84
• https://git.kernel.org/stable/c/730d0bb19507b9e19c2fe5343109ac618e2fbce5
• https://git.kernel.org/stable/c/9eed72e9534b10a6d9f8f5146feff3db53aebdba