Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Connectwise | Screenconnect | < 25.2.4 |
Related Weaknesses (CWE)
References
- https://www.connectwise.com/company/trust/advisoriesVendor Advisory
- https://www.connectwise.com/company/trust/security-bulletins/screenconnect-securVendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-US Government Resource
FAQ
What is CVE-2025-3935?
CVE-2025-3935 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ...
How severe is CVE-2025-3935?
CVE-2025-3935 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-3935?
Check the references section above for vendor advisories and patch information. Affected products include: Connectwise Screenconnect.