Intel

CVE-2018-3639: Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the add…

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 25 Feb 2020. It cites 4 public reports, the first from 25 Feb 2020.

How likely is exploitation in the next 30 days?

60.6%

EPSS score, percentile 99.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

5.5 Medium

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (12)

Which versions are affected?

Affected

Multiple

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

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.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

RHSA-2018:1689 (Vendor advisory)
RHSA-2018:2162 (Vendor advisory)
RHSA-2018:1641 (Vendor advisory)
USN-3680-1 (Vendor advisory)
RHSA-2018:1997 (Vendor advisory)
RHSA-2018:1665 (Vendor advisory)
RHSA-2018:3407 (Vendor advisory)
RHSA-2018:2164 (Vendor advisory)
RHSA-2018:2001 (Vendor advisory)
RHSA-2018:3423 (Vendor advisory)
RHSA-2018:2003 (Vendor advisory)
USN-3654-1 (Vendor advisory)

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (1 product)

Intel Corporation Multiple
Status	Versions
Affected	Multiple

Source: CVE List, as of 30 Oct 2026. About the data.

Weakness

CWE-203

CWE-203: Observable Discrepancy

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

Date	Event
22 May 2018	CVE record published
29 May 2026	CVE record last updated

References

135

135 more in the CVE record.

Known exploited Intel vulnerabilities

CVE-2015-2291: Intel Ethernet Diagnostics Driver for Windows Denial-of-Service Vulnerability (added 10 Feb 2023)
CVE-2017-5689: Intel Active Management Technology (AMT), Small Business Technology (SBT), and Standard Manageability Privilege Escalation Vulnerability (added 28 Jan 2022)