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Vulnerability record · CVE-2019-16517 · published 23 January 2020

CVE-2019-16517: Connectwise control origin validation error vulnerability

Connectwise · Control

An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is a CORS misconfiguration, which reflected the Origin provided by incoming requests. This allowed JavaScript running on any domain to interact with the server APIs and perform administrative actions, without the victim's knowledge.

9.8 CVSS 3.1 Critical EPSS 1.3% · top 29.9% CWE-346 · Origin validation error
9.8CVSS 3.1 base score, v2 7.5
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References, 4 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is a CORS misconfiguration, which reflected the Origin provided by incoming requests. This allowed JavaScript running on any domain to interact with the server APIs and perform administrative actions, without the victim's knowledge.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://blog.huntresslabs.com/validating-the-bishop-fox-findings-in-connectwise-control-9155eec36a34 ExploitThird Party Advisory
https://know.bishopfox.com/advisories Third Party Advisory
https://know.bishopfox.com/advisories/connectwise-control ExploitThird Party Advisory
https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-fox Third Party Advisory
https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-rese Third Party Advisory
https://blog.huntresslabs.com/validating-the-bishop-fox-findings-in-connectwise-control-9155eec36a34 ExploitThird Party Advisory
https://know.bishopfox.com/advisories Third Party Advisory
https://know.bishopfox.com/advisories/connectwise-control ExploitThird Party Advisory
https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-fox Third Party Advisory
https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-rese Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2023-25718Connectwise control improper verification of cryptographic signature vulnerabilityIn ConnectWise Control through 22.9.10032 (formerly known as ScreenConnect), after an executable file is signed, additional instructions can be added…EPSS 0.69%8.8CVE-2023-25719Connectwise control injection vulnerabilityConnectWise Control before 22.9.10032 (formerly known as ScreenConnect) fails to validate user-supplied parameters such as the Bin/ConnectWiseControl…EPSS 1.1%8.8CVE-2019-16513Connectwise control cross-site request forgery vulnerabilityAn issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. CSRF can be used to send API requests.EPSS 1.0%7.2CVE-2019-16514Connectwise control unrestricted file upload vulnerabilityAn issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. The server allows remote code execution. Administra…EPSS 4.2%6.5CVE-2019-16515Connectwise control vulnerabilityAn issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. Certain HTTP security headers are not used.EPSS 1.7%5.3CVE-2019-16516Connectwise control observable discrepancy vulnerabilityAn issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is a user enumeration vulnerability, allowing…EPSS 19%4.8CVE-2019-16512Connectwise control cross-site scripting vulnerabilityAn issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is stored XSS in the Appearance modifier.EPSS 1.2%9.4CVE-2025-34291Langflow CORS misconfiguration leads to token theft and RCELangflow up to and including 1.6.9 ships an overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) and a refresh token …KEVEPSS 93%analysed

Source: NIST National Vulnerability Database (record CVE-2019-16517), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.