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.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < 9cf7eb8919344932f909b2fac76296f7656fda8d
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < 9919021a3b7974ae66a5f9915e3a48c10cfd409b
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < 969bc6370334a5b4720c5470783295d6484bbc95
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < a3238b09c58f323e40743ce174cd0ab81b5c09ed
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < a8d17d22db591099519a89f14dd24810daba74c3
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < c2397b93fbb6f44a788fff30f99be2c20cc5e50f
fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 affected < d1ebfce2c1d161186a82e77590bf7da2ea1bce91
Linux Linux affected
Version Status Constraints
5.11 affected —
0 unaffected < 5.11
5.15.210 unaffected ≤ 5.15.*
6.1.176 unaffected ≤ 6.1.*
6.6.143 unaffected ≤ 6.6.*
6.12.92 unaffected ≤ 6.12.*
6.18.34 unaffected ≤ 6.18.*
7.0.11 unaffected ≤ 7.0.*
7.1 unaffected ≤ *

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/969bc6370334a5b4720c5470783295d6484bbc95 cve-icon
https://git.kernel.org/stable/c/9919021a3b7974ae66a5f9915e3a48c10cfd409b cve-icon
https://git.kernel.org/stable/c/9cf7eb8919344932f909b2fac76296f7656fda8d cve-icon
https://git.kernel.org/stable/c/a3238b09c58f323e40743ce174cd0ab81b5c09ed cve-icon
https://git.kernel.org/stable/c/a8d17d22db591099519a89f14dd24810daba74c3 cve-icon
https://git.kernel.org/stable/c/c2397b93fbb6f44a788fff30f99be2c20cc5e50f cve-icon
https://git.kernel.org/stable/c/d1ebfce2c1d161186a82e77590bf7da2ea1bce91 cve-icon
https://lore.kernel.org/linux-cve-announce/2026071928-CVE-2026-64137-f080@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-64137 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-64137 cve-icon
History

Mon, 20 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-280
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important

Sun, 19 Jul 2026 16:15:00 +0000

Type Values Removed Values Added
Description 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.
Title smb: client: require net admin for CIFS SWN netlink
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-19T15:40:31.045Z

Reserved: 2026-07-19T07:54:57.037Z

Link: CVE-2026-64137

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-19T00:00:00Z

Links: CVE-2026-64137 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses