known ransomware use

Microsoft Windows Server Message Block (SMBv1) Remote Code Execution Vulnerability

Added to KEV
2021-11-03
Federal due date
2022-05-03
Vendor
Microsoft
Product
Windows
EPSS
99.9th percentile (score 0.940, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2017-0143

CISA short description

Microsoft Windows Server Message Block 1.0 (SMBv1) contains an unspecified vulnerability that allows for remote code execution.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.