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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HConnectwise Screenconnect
APPConnectwise< 25.2.4
CISA KEV — detailsi
- Vendori
- ConnectWise ↗
- Producti
- ScreenConnect
- Added to KEVi
- June 2, 2025
- Remediation deadline (US Federal)i
- June 23, 2025(overdue)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
ConnectWise ScreenConnect contains an improper authentication vulnerability. This vulnerability could allow a ViewState code injection attack, which could allow remote code execution if machine keys are compromised.
Related vulnerabilities
Authentication Bypass w ConnectWise ScreenConnect — bezpośredni dostęp do systemów
ConnectWise ScreenConnect — instalacja niezaufanych rozszerzeń z RCE
ConnectWise ScreenConnect 23.9.7 and prior are affected by path-traversal vulnerability, which may allow an at...
ConnectWise ScreenConnect through 23.8.4 allows man-in-the-middle attackers to achieve remote code execution v...
In deployments using the ScreenConnect™ Certificate Signing Extension, encrypted configuration values includin...