Vulnerability in Linux

CVE-2026-64136

In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes. There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().

Vulnerability class: Race Condition

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (30.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-64136: held from 0.005 to 0.004.

EPSS over last 30 days · oldest: 0.005 · newest: 0.004 · change: -0.001

Affected products

  • Linux — versions 953953abb66e52c224057ab91e404284fefeab62, 601dd3b79769b38d30b693c40afdb2a4b7edf9d0, 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136
  • Linux Kernel — versions 7.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-64136?
CVE-2026-64136 is a critical-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 9.8/10. Published 2026-07-19.
How severe is CVE-2026-64136?
Critical severity. CVSS v3 base score is 9.8 out of 10.