CVE-2026-64136 Linux CVE debrief

Who should care

Linux kernel users and administrators should be aware of this vulnerability and take necessary actions to protect their systems. This includes reviewing and verifying the locking usage for tcon fields in the cifs code, monitoring system logs for potential issues related to SMB client, and applying the patch or updating to the latest Linux kernel version.

Technical summary

The vulnerability is related to the Linux kernel's SMB client implementation. A missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked() could lead to potential issues. The fix was introduced as part of the commit 96c4af418586 (cifs: Fix locking usage for tcon fields). This vulnerability may impact the stability and security of Linux kernel-based systems, particularly those using SMB client functionality.

Defensive priority

Medium

Recommended defensive actions

• Apply the patch or update to the latest Linux kernel version
• Review and verify the locking usage for tcon fields in the cifs code
• Monitor system logs for potential issues related to SMB client
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-19T16:17:55.463Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the official advisory. The vulnerability is related to the Linux kernel's SMB client implementation, and the fix was introduced as part of the commit 96c4af418586 (cifs: Fix locking usage for tcon fields).

Official resources