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CVE-2026-64137

Vulnerability intelligence

Published Jul 19, 2026Sources checked Oct 27, 2026
7.8HIGHCVSS out of 10
What this means

Review the available evidence

CVE-2026-64137 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Ubuntu Security Notices guidance

Vendor revision: Sep 29, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

Ubuntu Security Notices guidance

Vendor revision: Sep 25, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

Ubuntu Security Notices guidance

Vendor revision: Sep 22, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

CISA KEVNot listedBased on the latest collected catalog
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview

What is CVE-2026-64137?

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.

Source: NVD