Updated daily · April 30, 2026

Top Cyber Vulnerabilities Affecting Small Businesses

Which vulnerabilities could hit small businesses next? Ranked daily by SMB Attack Probability Score — combining exploit likelihood, active exploitation, and real-world SMB software prevalence.

Forecast window: Next 30 days
Last updated: April 30, 2026
Data sources: NVD · CISA KEV · EPSS · GHSA
31
Critical threats
24
High risk
46
KEV (exploited)
17,126
Total monitored

Top 10 Vulnerabilities Likely to Impact SMBs This Month

1
CVE-2025-53770
KEVEXPLOIT
95 /100
critical
9.8
CVSS v3
90.5%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

This vulnerability affects software widely used in small business environments. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and exploitation probability is 90% in the next 30 days and SMB Attack Probability Score is 95/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
2
CVE-2026-21513
KEVEXPLOIT
90 /100
critical
8.8
CVSS v3
4.8%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 90/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
3
CVE-2025-54313
KEVEXPLOIT
89 /100
critical
7.5
CVSS v3
6.7%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 89/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
4
CVE-2026-3909
KEVEXPLOIT
89 /100
critical
8.8
CVSS v3
27.1%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 89/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
5
CVE-2026-21510
KEVEXPLOIT
88 /100
critical
8.8
CVSS v3
3.1%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 88/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
6
CVE-2026-3910
KEVEXPLOIT
87 /100
critical
8.8
CVSS v3
21.9%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 87/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
7
CVE-2025-2783
KEVEXPLOIT
87 /100
critical
8.3
CVSS v3
35.4%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 87/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
8
CVE-2025-64446
KEVEXPLOIT
87 /100
critical
9.8
CVSS v3
89.0%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

This vulnerability affects software widely used in small business environments. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and exploitation probability is 89% in the next 30 days and SMB Attack Probability Score is 87/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
9
CVE-2025-24813
KEVEXPLOIT
86 /100
critical
9.8
CVSS v3
94.2%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

This vulnerability affects software widely used in small business environments. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and exploitation probability is 94% in the next 30 days and SMB Attack Probability Score is 86/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →
10
CVE-2025-24054
KEVEXPLOIT
84 /100
critical
6.5
CVSS v3
11.9%
EPSS
💻 Operating system
Est. downtime: 5–14 days · €20K–€150K
Why this matters for small businesses

Microsoft Windows powers the majority of SMB workstations and servers worldwide. An operating system vulnerability can allow attackers to escalate from a standard user to full system control, enabling network-wide ransomware deployment. Risk is elevated because CISA has confirmed active exploitation in the wild and a working exploit is publicly available and SMB Attack Probability Score is 84/100. For a typical small business, exploitation could mean 5–14 days of downtime and recovery costs between €20K–€150K.

View full analysis, remediation steps, and SMB impact →

Most Vulnerable Software Used by Small Businesses

SoftwareCVEsCriticalHighKEVRisk level
Microsoft
383
17
10
22
critical
Fortinet
73
3
3
critical
Apache
52
1
1
critical
Cisco
20
1
1
high
Adobe
202
medium
Oracle
77
medium
QNAP
50
medium
TP-Link
19
medium
Synology
11
medium
NETGEAR
11
medium

Browse Vulnerabilities by Vendor

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