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CVE-2025-3935

8.1
HIGHCVSS v3.1 Base Score
12.03%
LOW RiskEPSS (94th percentile)
KEV

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.

Published: 4/25/2025
Modified: 10/24/2025
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ACTIVELY EXPLOITED IN THE WILD

This vulnerability is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Vulnerability Name:

ConnectWise ScreenConnect Improper Authentication Vulnerability

Vendor / Product:

ConnectWise ScreenConnect

Required Action:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Due Date: 6/23/2025(OVERDUE)
Added to KEV:

6/2/2025

Notes:

https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4 ; https://nvd.nist.gov/vuln/detail/CVE-2025-3935

Vulnerability Summary

CVSS v3 Score

8.1HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score (Exploitation Probability)

12.03%LOW Exploitation Risk
94th percentile

This vulnerability has a 12.03% probability of being exploited in the next 30 days, ranking higher than 94% of all scored CVEs.

CWE Classification

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Similar SeverityHIGH