CVE-2026-64137

High

In the Linux kernel, the following vulnerability has been resolved: smb: client: require net admin for CIFS SWN netlink CIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command. The intended sender is the cifs.witness helper, but the generic-netlink operation currently has no capability flag, so any local process can send RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness handler. The same family exposes CIFS_GENL_MCGRP_SWN without multicast-group capability flags. Register messages sent to that group include the witness registration id and, for NTLM-authenticated mounts, the username, domain, and password attributes copied from the CIFS session. An unprivileged local process should not be able to join that group and receive those messages. Require CAP_NET_ADMIN for incoming SWN_NOTIFY commands with GENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for joining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN. The cifs.witness service runs with the privileges needed for both operations.

Package Linux Kernel
Published 2026-07-19
Last modified 2026-08-13
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.11 and later are affected. Fixed in 5.15.210, 6.1.176, 6.6.143, 6.12.92, 6.18.34, 7.0.11, 7.1 and their respective stable series.

Affected from
≥ 5.11
Fixed in
✓ 5.15.210 5.15.x ✓ 6.1.176 6.1.x ✓ 6.6.143 6.6.x ✓ 6.12.92 6.12.x ✓ 6.18.34 6.18.x ✓ 7.0.11 7.0.x ✓ 7.1

References

7 total
Showing 5 of 7 references View all on NVD

Frequently asked questions

  • What is CVE-2026-64137?

    CVE-2026-64137 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.11 onward and has been patched in 5.15.210, 6.1.176, 6.6.143 and others. CVE-2026-64137 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-64137?

    CVE-2026-64137 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-64137?

    Yes. CVE-2026-64137 has been patched. Fixed versions include 5.15.210, 6.1.176, 6.6.143 and others. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-64137 actively exploited?

    No. CVE-2026-64137 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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