Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 3.4%; technical severity is CVSS 7.2.
ScreenConnect versions 25.2.3 and earlier versions may be susceptible to a ViewState code injection attack. ASP.NET Web Forms use ViewState to preserve page and control state, with data encoded using Base64 protected by machine keys. It is important to note that to obtain these machine keys, privileged system level access must be obtained. If these machine keys are compromised, attackers could create and send a malicious ViewState to the website, potentially leading to remote code execution on the server. The risk does not originate from a vulnerability introduced by ScreenConnect, but from platform level behavior. This had no direct impact to ScreenConnect Client. ScreenConnect 2025.4 patch disables ViewState and removes any dependency on it.
Who should care
- Teams operating ScreenConnect
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether ScreenConnect is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Vendor advisory from www.connectwise.com
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Patch
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-287
- Affected versions
- ConnectWise ScreenConnect (End Excluding 25.2.4)
- Fixed versions
- ConnectWise ScreenConnect (Fixed from 25.2.4)
- Published
- 25 April 2025
- Attack vector
- Network
- Privileges required
- High
- User interaction
- None
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 3.4%
- Signal calculated at 66