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.
CVE-2019-16517
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 55% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.8
- EG Score
- 9.8(medium)
- EPSS
- 67.6%
- KEV
- Not listed
Published
January 23, 2020
Last Modified
November 21, 2024
Advisory Details (4)
Auto-updated Jul 5, 2026ConnectWise Control 'Attack Chain' Exploit: 20 Questions For Security Researcher Bishop Fox | CRN
https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-researcher-bishop-foxConnectWise Control MSP Security Vulnerabilities Are ‘Severe:’ Bishop Fox | CRN
https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-foxConnectWise Control 19.3.25270.7185 - Eight… | Bishop Fox
https://know.bishopfox.com/advisories/connectwise-controlBishop Fox Offensive Security Advisories Blog | Bishop Fox
https://know.bishopfox.com/advisoriesWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 38× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:24 UTCEPSS rescore
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- 2026-07-09 19:06 UTCEPSS rescore
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- 2026-06-28 04:54 UTCEPSS rescore
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- 2026-06-21 14:54 UTCEPSS rescore
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- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-12 23:09 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
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- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
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- 2026-06-06 13:45 UTCEPSS rescore
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- 2026-06-04 13:10 UTCEPSS rescore
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- 2026-06-02 20:11 UTCEPSS rescore
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- 2026-06-01 13:50 UTCEPSS rescore
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- 2026-05-31 22:29 UTCEPSS rescore
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- 2026-05-31 00:14 UTCEPSS rescore
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- 2026-05-29 13:42 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:38 UTCEPSS rescore
- 2026-05-27 08:46 UTCEG score recompute
- 2026-05-27 08:46 UTCGHSA enrichment
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-25 01:13 UTCOSV refresh
Frequently asked(5)
What is CVE-2019-16517?
When was CVE-2019-16517 disclosed?
Is CVE-2019-16517 actively exploited?
What is the CVSS score of CVE-2019-16517?
How do I remediate CVE-2019-16517?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2019-16517
Is Your Infrastructure Affected by CVE-2019-16517?
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