What is CVE-2026-64136?

CVE-2026-64136 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 6.6.128 onward and patched in 6.6.142, 6.12.92, 6.18.34 and others. CVE-2026-64136 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64136?

CVE-2026-64136 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-64136?

Yes, CVE-2026-64136 has been patched. Fixed versions include 6.6.142, 6.12.92, 6.18.34 and others. If you are running Linux kernel 6.6.128 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64136 actively exploited?

CVE-2026-64136 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64136

Critical

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().

Package Linux Kernel

Published 2026-07-19

Last modified 2026-08-13

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0 and later are affected. Fixed in 6.6.142, 6.12.92, 6.18.34, 7.0.11, 7.1 and their respective stable series.

Affected from

≥ 6.6.128 ≥ 6.12.75 ≥ 6.18.16 ≥ 6.19.6 ≥ 7.0

Fixed in

✓ 6.6.142 6.6.x ✓ 6.12.92 6.12.x ✓ 6.18.34 6.18.x ✓ 7.0.11 7.0.x ✓ 7.1

References

5 total

Kernel Git
https://git.kernel.org/stable/c/13fb413ae22a37c69341918a6d651d19a9b0b9b7

Patch
Kernel Git
https://git.kernel.org/stable/c/4d8690dace005a38e6dbde9ecce2da3ad85c7c41

Patch
Kernel Git
https://git.kernel.org/stable/c/7df1df6f40c0720d30206aa35c0343b962350e0d

Patch
Kernel Git
https://git.kernel.org/stable/c/bf4ebdb19ff9b3cdf992b50715fe61633327416a

Patch
Kernel Git
https://git.kernel.org/stable/c/e374f4e496fef8168784f93a4477d67be34485fd

Patch

Details

CVE ID CVE-2026-64136

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-07-19

Modified 2026-08-13

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64136?

CVE-2026-64136 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 6.6.128 onward and has been patched in 6.6.142, 6.12.92, 6.18.34 and others. CVE-2026-64136 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64136?

CVE-2026-64136 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-64136?

Yes. CVE-2026-64136 has been patched. Fixed versions include 6.6.142, 6.12.92, 6.18.34 and others. If you are running Linux kernel 6.6.128 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64136 actively exploited?

No. CVE-2026-64136 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.