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Vulnerabilities/CVE-2026-64034Public Intelligence Dossier
Source: linux · Limited verification•Last verified: •Collection Running
CVE-2026-64034Unknown / EvaluatingCRITICAL (raw)CVSS 9.3CWE-367

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

Published: 19 Jul 2026•Last updated: 16 Oct 2026, 09:49 PM IST•Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dossier completeness: source-provided sections 2 / 3 · rule guidance not available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
9.3CRITICAL (raw)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Metric source416baaa9-dc9f-4396-8d5f-8c081fb06d67
EPSS probability
0.1%0.001
Percentile1st
Weakness type
CWE-367
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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().

SOC priority

High Severity / Review

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; CRITICAL severity; Critical CVSS without confirmed KEV exploitation

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • linux linux kernel · >= 5.13 < 5.15.209; >= 5.16 < 6.1.175; >= 6.2 < 6.6.142; >= 6.7 < 6.12.92; >= 6.13 < 6.18.34; >= 6.19 < 7.0.11; 7.1 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

No rule-based guidance for this vulnerability class

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*

Evidence & Provenance

3 public sources
git.kernel.orgSource recordnvd.nist.govSource recordgit.kernel.orgSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-64034
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-64034
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-64034"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.