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CVE Record

CVE-2018-3639: Systems with microprocessors utilizing speculative execution and speculative execution of memory reads befo...

Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the addresses of all prior memory writes are known may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis, aka Speculative Store Bypass (SSB), Variant 4.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2018-3639 is a hardware-class information disclosure issue known as Speculative Store Bypass, or Variant 4. A local user on an affected system may infer sensitive data through side-channel behavior. It is not a remote code execution issue, but it matters for shared servers, workstations, and multi-user environments.

Executive priority

Handle through standard vulnerability management, with accelerated attention for shared infrastructure. The business risk is potential data disclosure from local code execution, not direct remote takeover based on the supplied evidence.

Technical view

Affected microprocessors may speculatively read memory before prior write addresses are resolved. That behavior can expose data through side-channel analysis to an attacker with local user access. The CVSS 3.1 score is 5.5 because confidentiality impact is high, but attack access is local and requires low privileges.

Likely exposure

Exposure is most relevant on systems using affected Intel processors where OS, kernel, hypervisor, or microcode updates from vendors such as Red Hat or Ubuntu have not been applied. Multi-user and shared compute environments carry higher practical concern than single-user devices.

Exploitation context

The provided bundle does not show CISA KEV listing or cited active exploitation. The issue requires local user access and side-channel analysis. Treat it as a defense-in-depth and shared-hosting risk rather than evidence of current broad exploitation.

Researcher notes

The source bundle identifies CWE-203 and CVSS AV:L/PR:L/UI:N/C:H. Product and version detail is broad, so validation should be advisory-driven. Do not assume all mitigations apply uniformly across processor, OS, and hypervisor combinations.

Mitigation direction

  • Apply relevant vendor security updates for affected operating systems and platforms.
  • Review Red Hat, Ubuntu, and hardware vendor guidance for applicable microcode or kernel updates.
  • Prioritize shared hosts, virtualization platforms, and systems running untrusted local workloads.
  • Track vendor guidance for performance or configuration tradeoffs before enabling optional mitigations.

Validation and detection

  • Inventory systems using affected Intel processor families where local users can run code.
  • Check installed OS, kernel, hypervisor, and microcode versions against vendor advisories.
  • Confirm security updates referenced by your platform vendor are deployed.
  • Validate compensating controls for shared or untrusted local execution environments.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-203: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2018-3639 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
2ADP providers
39Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2018-3639Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc

Source materials

  • CVE List V5 sourceCVE List V5
  • RHSA-2018:1689CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:2162CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1641CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • USN-3680-1CVE reference, intel · vendor-advisory, x_refsource_UBUNTU
  • RHSA-2018:1997CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1665CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:3407CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:2164CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:2001CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:3423CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:2003CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • USN-3654-1CVE reference, intel · vendor-advisory, x_refsource_UBUNTU
  • RHSA-2018:1645CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1643CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1652CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:3424CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:3402CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • TA18-141ACVE reference, intel · third-party-advisory, x_refsource_CERT
  • RHSA-2018:1656CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1664CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:2258CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1688CVE reference, intel · vendor-advisory, x_refsource_REDHAT
  • RHSA-2018:1658CVE reference, intel · vendor-advisory, x_refsource_REDHAT
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Intel CorporationMultipleMultipleListed
Weakness

CWE details

CWE-203

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-203 · source CWE mapping

Observable Discrepancy

Observable Discrepancy represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs