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Core I3Hardware / appliance · Intel

CVE-2018-3646

MEDIUM · 5.6 CVSS v3.1 Published 2018-08-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Systems with microprocessors utilizing speculative execution and address translations may allow unauthorized disclosure of information residing in the L1 data cache to an attacker with local user access with guest OS privilege via a terminal page fault and a side-channel analysis.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CVE-2018-3646 (Spectre Variant 3a/Rogue System Register Read) is a speculative execution vulnerability in Intel microprocessors that allows a local attacker with guest OS privileges to read host system registers via speculative execution, potentially exposing sensitive information from the L1 data cache through terminal page fault side-channel analysis.

MitigationApply Intel CPU microcode updates, vendor OS patches, and virtualization platform updates; consider disabling hyper-threading as a defensive measure where applicable.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Core I3Hardware / appliance
Affected:= 330e= 330m= 330um= 350m= 370m= 380m= 380um= 390m= 530= 540= 550= 560
Core I5Hardware / appliance
Affected:= 430m= 430um= 450m= 460m= 470um= 480m= 520e= 520m= 520um= 540m= 540um= 560m
Core I7Hardware / appliance
Affected:= 7y75= 610e= 620le= 620lm= 620m= 620ue= 620um= 640lm= 640m= 640um= 660lm= 660ue
Core MHardware / appliance
Affected:= 5y10= 5y10a= 5y10c= 5y31= 5y51= 5y70= 5y71
Core M3Hardware / appliance
Affected:= 6y30= 7y30= 7y32
Core M5Hardware / appliance
Affected:= 6y54= 6y57
Core M7Hardware / appliance
Affected:= 6y75
XeonHardware / appliance
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the CPU model
    Run 'lscpu' or 'cat /proc/cpuinfo' and locate the 'model name' field (e.g., Intel Core i5-520M)
    Affected if The CPU model number (e.g., 520m) matches one of the affected variants listed in the CVE (for i3: 330e through 560; i5: 430m through 560m; i7: 7y75 through 660ue; Core M: 5y10 through 5y71; Core M3: 6y30 through 7y32; Core M5: 6y54 through 6y57; Core M7: 6y75; or any Xeon processor)
  2. Check if virtualization is in use
    Look for hypervisor presence via 'lscpu' (Hypervisor vendor line) or 'systemd-detect-virt'
    Affected if The system runs as a virtual machine (guest) on an Intel host, allowing a guest OS attacker to potentially reach host system registers
  3. Verify hyper-threading status
    Check CPU sibling info: 'lscpu | grep -i thread' or examine /sys/devices/system/cpu/cpu*/topology/thread_siblings_list
    Affected if Hyper-threading is enabled, increasing the attack surface for side-channel leakage from sibling threads
  4. Check vulnerability mitigation status
    On Linux, examine /sys/devices/system/cpu/vulnerabilities/ for relevant flags (e.g., 'spec_store_bypass' or similar CPU mitigation files); on Windows, run 'systeminfo' and look for KB articles or use 'wmic cpu get caption,version' for microcode level
    Affected if The system shows 'Vulnerable' or no mitigation flags are present, indicating microcode updates or OS patches have not been applied

A user is affected if their Intel CPU model matches the affected list, the system is used in a virtualized environment, and no microcode or OS-level mitigations have been applied to block speculative execution side-channel exploitation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Intel CPU microcode updates, vendor OS patches, and virtualization platform updates; consider disabling hyper-threading as a defensive measure where applicable.

Fix this in Core I3 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-3646 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data