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().
CSIRTS triage
- What
- Multiple kernel flaws including NTFS file system out-of-bounds read, AMD processor floating point unit data exposure, and AMD Zen 2 operation cache isolation failure.
- Who is affected
- Systems running affected Linux kernel versions; local attackers on systems with NTFS mounted or AMD processors.
- Urgency
- Moderate to high — local attackers can gain privilege escalation and information disclosure; apply patches promptly.
- Action
- Apply kernel security updates provided by distribution maintainer.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.
Advisory coverage (25)
- unknownUSN-8729-1: Linux kernel vulnerabilitiesubuntu · 2026-09-07
- unknownexploitedUSN-8728-1: Linux kernel (GCP) vulnerabilitiesubuntu · 2026-09-07
- unknownUSN-8668-1: Linux kernel (GCP) vulnerabilitiesubuntu · 2026-08-21
- unknownUSN-8664-1: Linux kernel (NVIDIA BaseOS) vulnerabilitiesubuntu · 2026-08-20
- unknownUSN-8663-1: Linux kernel (NVIDIA) vulnerabilitiesubuntu · 2026-08-20
- unknownUSN-8620-4: Linux kernel (Intel IoTG) vulnerabilitiesubuntu · 2026-07-31
- unknownUSN-8620-3: Linux kernel (Intel IoTG) vulnerabilitiesubuntu · 2026-07-31
- unknownUSN-8620-2: Linux kernel (Azure FIPS) vulnerabilitiesubuntu · 2026-07-29
- highUSN-8620-1: Linux kernel vulnerabilitiesubuntu · 2026-07-28
- highUSN-8618-1: Linux kernel vulnerabilitiesubuntu · 2026-07-28
- highUSN-8610-1: Linux kernel (Azure CVM) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8575-3: Linux kernel vulnerabilitiesubuntu · 2026-07-24
- highUSN-8609-1: Linux kernel (Azure CVM) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8608-1: Linux kernel (Azure FIPS) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8607-1: Linux kernel (Azure CVM) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8606-1: Linux kernel (Azure) vulnerabilitiesubuntu · 2026-07-24
- unknownUSN-8605-1: Linux kernel (Azure CVM) vulnerabilitiesubuntu · 2026-07-24
- unknownUSN-8604-1: Linux kernel (Azure) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8603-1: Linux kernel (Azure) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8576-2: Linux kernel (NVIDIA Tegra) vulnerabilitiesubuntu · 2026-07-23
- highUSN-8575-2: Linux kernel vulnerabilitiesubuntu · 2026-07-23
- highUSN-8593-1: Linux kernel vulnerabilitiesubuntu · 2026-07-23
- highUSN-8576-1: Linux kernel (NVIDIA Tegra) vulnerabilitiesubuntu · 2026-07-21
- highUSN-8575-1: Linux kernel vulnerabilitiesubuntu · 2026-07-21
- criticalCVE-2026-64034: In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix TOCTOU doub…nvd · 2026-07-19
External references
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