Use-after-free in Linux kernel - CVE-2026-89637
Published: September 12, 2026
Vulnerability identifier: #VU149166
CSH Severity: Medium
CVSS v4: 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]
CVE-ID: CVE-2026-89637
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-89637
Install security update from vendor's repository.