Linux kernel flaw allowing kernel memory corruption; Linux is widely deployed across servers and VMs and failure can enable escalation/host compromise.
CVE-2026-64034
Linux kernel mana driver TOCTOU allows DMA-supplied value to bypass bounds check
Is CVE-2026-64034 being exploited?
Not confirmed. CVE-2026-64034 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.15% probability of exploitation in the next 30 days.
How severe is CVE-2026-64034?
CVE-2026-64034 is rated Critical with a CVSS score of 9.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-64034?
Yes. A fix has been recorded for CVE-2026-64034. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64034 affect?
CVE-2026-64034 affects Linux kernel (mana driver), Systems with DMA-capable NICs, Confidential VMs (SEV-SNP/TDX). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64034?
Apply vendor kernel update that fixes mana driver and reboot affected hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
TOCTOU on DMA-fed hwc_msg_id can cause kernel memory corruption, enabling local privilege escalation, code execution, or kernel crash; host compromise in Confidential VMs.
Immediate action required
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < a201c66edf2ebc6cfdc3813a889ba20fecebfae3
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 70ad2dff8d052a85dfef15715b531f38a29108cf
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 566f42fb67a7ebfed6650e407e5b72e6b3e83bf7
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 6180a06bbc99fd9114b8db4be6c4d46e40f046ef
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 09ec063d87c2dd3fa6f3561361a017bd882e9f37
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 3c4db56ccd13dd020fbf43afabaee74a40ec75e4
- affected>= ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f and < 35f0f0a2536a4d604b4dbad92c85c4a8fdebb870
- affected5.13
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.