CVE-2019-16517: An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2019-16517 is a critical-severity flaw (CVSS 9.8) affecting control. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-346
Published	2020-01-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: connectwise

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-01-23 18:15 UTCPublished CVE record published
2026-06-17 02:22 UTCUpdated Record last modified

connectwise control DOWNGRADE

Affected: 19.3.25270.7185

Fixed in: no fixed release known

Safe to downgrade to: a release before 19.3.25270.7185

1. Check installed version

apt-cache policy control || rpm -q control || control --version

2. No fixed release: DOWNGRADE to a release before 19.3.25270.7185 (Debian / Ubuntu)

apt-cache madison control sudo apt install control=<VERSION_BEFORE_19.3.25270.7185> sudo apt-mark hold control

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list control sudo dnf downgrade control-<VERSION_BEFORE_19.3.25270.7185> sudo dnf versionlock add control

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-16517?

control: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-16517 being exploited?

CVE-2019-16517 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-16517 affect?

CVE-2019-16517 affects control. Severity is critical (CVSS 9.8). 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 i

How urgent is CVE-2019-16517?

Priority 62/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

ConnectWise ScreenConnect vulnerabilities

Related CVEs

CVE-2023-25719 HIGH 8.8 UPGRADE ConnectWise Control before 22.9.10032 (formerly known as ScreenConnect) fails to validate user-supplied parame
CVE-2023-25718 CRITICAL 9.8 UPGRADE In ConnectWise Control through 22.9.10032 (formerly known as ScreenConnect), after an executable file is signe
CVE-2021-36763 HIGH 7.5 UPGRADE UPGRADE In CODESYS V3 web server before 3.5.17.10, files or directories are accessible to External Parties.
CVE-2021-33485 CRITICAL 9.8 UPGRADE UPGRADE CODESYS Control Runtime system before 3.5.17.10 has a Heap-based Buffer Overflow.
CVE-2019-16516 MEDIUM 5.3 UPGRADE An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185

References

← Back to latest CVEs