CVE-2019-16517
This allowed JavaScript running on any domain to interact with the server APIs and perform administrative actions, without the victim's knowledge.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.34% probability · 71th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-346
- Affected
- connectwise/control
- Source
- cve@mitre.org
EPSS 1.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://blog.huntresslabs.com/validating-the-bishop-fox-findings-in-connectwise-control-9155eec36a34Exploit, Third Party Advisory
- https://know.bishopfox.com/advisoriesThird Party Advisory
- https://know.bishopfox.com/advisories/connectwise-controlExploit, Third Party Advisory
- https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-foxThird Party Advisory
- https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-researcher-bishop-foxThird Party Advisory
- https://blog.huntresslabs.com/validating-the-bishop-fox-findings-in-connectwise-control-9155eec36a34Exploit, Third Party Advisory
- https://know.bishopfox.com/advisoriesThird Party Advisory
- https://know.bishopfox.com/advisories/connectwise-controlExploit, Third Party Advisory
- https://www.crn.com/news/managed-services/connectwise-control-msp-security-vulnerabilities-are-severe-bishop-foxThird Party Advisory
- https://www.crn.com/slide-shows/managed-services/connectwise-control-attack-chain-exploit-20-questions-for-security-researcher-bishop-foxThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.