known ransomware use

Kaseya Virtual System/Server Administrator (VSA) Information Disclosure Vulnerability

Added to KEV
2021-11-03
Federal due date
2021-11-17
Vendor
Kaseya
Product
Virtual System/Server Administrator (VSA)
EPSS
98.1th percentile (score 0.541, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2021-30116

CISA short description

Kaseya Virtual System/Server Administrator (VSA) contains an information disclosure vulnerability allowing an attacker to obtain the sessionId that can be used to execute further attacks against the system.

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.