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CVE-2026-64034

9.3 · CRITICAL

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 r…

Published Jul 19, 2026EPSS 0.11%

Overview

CVE-2026-64034 is a critical-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 9.3 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.3, rated CRITICAL. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical description

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().

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/09ec063d87c2dd3fa6f3561361a017bd882e9f37Refgit.kernel.org/stable/c/35f0f0a2536a4d604b4dbad92c85c4a8fdebb870Refgit.kernel.org/stable/c/3c4db56ccd13dd020fbf43afabaee74a40ec75e4Refgit.kernel.org/stable/c/566f42fb67a7ebfed6650e407e5b72e6b3e83bf7Refgit.kernel.org/stable/c/6180a06bbc99fd9114b8db4be6c4d46e40f046efRefgit.kernel.org/stable/c/70ad2dff8d052a85dfef15715b531f38a29108cfRefgit.kernel.org/stable/c/a201c66edf2ebc6cfdc3813a889ba20fecebfae3

How CyberStrike helps

Frequently asked questions

What is CVE-2026-64034?

CVE-2026-64034 is a critical-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 9.3 (CRITICAL).

How severe is CVE-2026-64034?

This vulnerability has a CVSS 3.1 base score of 9.3, rated CRITICAL. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-64034?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-64034?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-64034 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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