CVE-2026-64136Network attack vector

Unspecified impact via unlocked tcon reference increment

Published Jul 19, 2026 · Updated Jul 19, 2026

Race condition in the Linux Kernel SMB client allows remote attackers to cause unspecified impact through network traffic. smb2_find_smb_sess_tcon_unlocked increments tc_count without holding tc_lock after locking was moved from cifs_tcp_ses_lock. The CNA rates the flaw as remotely reachable without privileges or user interaction, but it does not disclose the triggering SMB exchange or concrete consequence.

CVSS severity9.8
Critical
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Race condition in the Linux Kernel SMB client allows remote attackers to cause unspecified impact through network traffic. smb2_find_smb_sess_tcon_unlocked increments tc_count without holding tc_lock after locking was moved from cifs_tcp_ses_lock. The CNA rates the flaw as remotely reachable without privileges or user interaction, but it does not disclose the triggering SMB exchange or concrete consequence.

The record

CVE
CVE-2026-64136
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3969db6b22e3d90d8c5f22ac1a7fe0350a94c136 <bf4ebdb19ff9b3cdf992b50715fe61633327416a
  2. Affected versionversion=601dd3b79769b38d30b693c40afdb2a4b7edf9d0 <13fb413ae22a37c69341918a6d651d19a9b0b9b7
  3. Affected versionversion=6.12.75 <6.12.92
  4. Affected versionversion=6.18.16 <6.18.34
  5. Affected versionversion=6.19.6 <6.20
  6. Affected versionversion=6.6.128 <6.6.142
  7. Affected versionversion=7.0
  8. Affected versionversion=8c59eeeeffa1524ef57e173a89a1a3ff539888d5
  9. Affected versionversion=953953abb66e52c224057ab91e404284fefeab62 <7df1df6f40c0720d30206aa35c0343b962350e0d
  10. Affected versionversion=96c4af418586ee9a6aab61738644366426e05316 <4d8690dace005a38e6dbde9ecce2da3ad85c7c41
  11. Affected versionversion=96c4af418586ee9a6aab61738644366426e05316 <e374f4e496fef8168784f93a4477d67be34485fd

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3969db6b22e3d90d8c5f22ac1a7fe0350a94c136 <bf4ebdb19ff9b3cdf992b50715fe61633327416a; version=601dd3b79769b38d30b693c40afdb2a4b7edf9d0 <13fb413ae22a37c69341918a6d651d19a9b0b9b7; version=6.12.75 <6.12.92; version=6.18.16 <6.18.34; version=6.19.6 <6.20; version=6.6.128 <6.6.142; version=7.0; version=8c59eeeeffa1524ef57e173a89a1a3ff539888d5; version=953953abb66e52c224057ab91e404284fefeab62 <7df1df6f40c0720d30206aa35c0343b962350e0d; version=96c4af418586ee9a6aab61738644366426e05316 <4d8690dace005a38e6dbde9ecce2da3ad85c7c41; version=96c4af418586ee9a6aab61738644366426e05316 <e374f4e496fef8168784f93a4477d67be34485fd

Published CVSS scores

9.8Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo