CVE-2018-3639 Public exploit Medium · 5.5 EPSS 60.6%
Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the…
Intel Corporation · Multiple
Summary
The flaw affects systems using Intel microprocessors that perform speculative execution, specifically speculative reads of memory before the addresses of all prior memory writes are known, a behaviour known as Speculative Store Bypass (Variant 4). An attacker with local user access and no user interaction can use a side-channel analysis to disclose information they should not be able to read.
Official description · CVE.org
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.
Priority scorePatchfirst’s 0 to 100 ranking. It adds points for CISA KEV listing, ransomware use, EPSS, threat reports, public exploit code and CVSS. Every CVE page shows the breakdown. Breakdown
74.4 / 100
- Exploited
- Yes, in VulnCheck KEV
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 21 months after disclosure. Public exploit code (Exploit-DB) was available the same day.
- First seen exploitedVulnCheck KEV evidence+21 mo
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
What security researchers reported
Not named in any threat report yetAlso mentioned in 1 community threat pulse (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- CVE Data16 Feb 2026