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CVE-2026-64034

Vulnerability intelligence

Published Jul 19, 2026Sources checked Oct 27, 2026
9.3CRITICALCVSS out of 10
What this means

Review the available evidence

CVE-2026-64034 and is rated Critical severity with a CVSS score of 9.3. 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-2026-64034?

In the Linux kernel, the following vulnerability has been resolved:

net: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer

In mana_hwc_rx_event_handler(), resp->response.hwc_msg_id is read from DMA-coherent memory and bounds-checked, then mana_hwc_handle_resp() re-reads the same field from the same DMA buffer for test_bit() and pointer arithmetic.

DMA-coherent memory is mapped uncacheable on x86 and is shared, unencrypted, in Confidential VMs (SEV-SNP/TDX), so each load goes directly to host-visible memory. A H/W can modify the value between the check and the use, bypassing the bounds validation.

Fix this by reading hwc_msg_id exactly once using READ_ONCE() into a stack-local variable in mana_hwc_rx_event_handler(), and passing the validated value as a parameter to mana_hwc_handle_resp().

Source: NVD