An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is a user enumeration vulnerability, allowing an unauthenticated attacker to determine with certainty if an account exists for a given username.
https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-researcher-bishop-fox
https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-fox
https://know.bishopfox.com/advisories
https://know.bishopfox.com/advisories/connectwise-control
https://blog.huntresslabs.com/validating-the-bishop-fox-findings-in-connectwise-control-9155eec36a34
http://packetstormsecurity.com/files/165432/ConnectWise-Control-19.2.24707-Username-Enumeration.html
Source: Mitre, NVD
Published: 2020-01-23
Updated: 2026-06-17
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS: 0.19097