ScreenConnect Exposure to ASP.NET ViewState Code Injection
At a glance
Severity
HIGH 8.1
Exploitation
Known exploited (CISA KEV) · added 2025-06-02 Exploited per ENISA since 2025-06-02
EPSS
EPSS 3.60 % · percentile 89 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
ConnectWise
NVD status
Analyzed
Description
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.
