CVE-2026-64034

A flaw was found in the Linux kernel's mana network driver. This Time-of-Check to Time-of-Use (TOCTOU) vulnerability allows a hardware component to modify a message identifier (hwc_msg_id) in Direct Memory Access (DMA) memory after it has been validated but before it is used. This manipulation bypasses critical bounds validation, potentially leading to unexpected system behavior or security bypasses, particularly in Confidential Virtual Machines (CVMs) where DMA memory is shared and unencrypted.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Prevent the MANA driver module from loading if Microsoft Azure Network Adapter hardware is not required.

Create the file /etc/modprobe.d/mana.conf with the following entry:

install mana /bin/true

If the mana module is currently loaded, the system must be rebooted for this configuration to take effect.

Warning: Disabling this driver will incapacitate network interfaces that depend on Microsoft Azure Network Adapter hardware, which may result in a total loss of network connectivity if it is the primary interface. System reboots will interrupt running services and network connections.