CVE-2026-64034
Linux kernel vulnerability
- Published19 Jul 2026
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().
CVSS 3.1 breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HRemediation
No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.
References
- https://git.kernel.org/stable/c/09ec063d87c2dd3fa6f3561361a017bd882e9f37
- https://git.kernel.org/stable/c/35f0f0a2536a4d604b4dbad92c85c4a8fdebb870
- https://git.kernel.org/stable/c/3c4db56ccd13dd020fbf43afabaee74a40ec75e4
- https://git.kernel.org/stable/c/566f42fb67a7ebfed6650e407e5b72e6b3e83bf7
- https://git.kernel.org/stable/c/6180a06bbc99fd9114b8db4be6c4d46e40f046ef
- https://git.kernel.org/stable/c/70ad2dff8d052a85dfef15715b531f38a29108cf
- https://git.kernel.org/stable/c/a201c66edf2ebc6cfdc3813a889ba20fecebfae3
Frequently asked
Is CVE-2026-64034 being actively exploited?
CVE-2026-64034 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.15%.
How severe is CVE-2026-64034?
CVE-2026-64034 has a CVSS 3.1 base score of 9.3, rated critical. EPSS estimates a 0.15% probability of exploitation.
How do I fix CVE-2026-64034?
Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-64034 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.