Deserialization in Connectwise Screenconnect
CVE-2025-3935
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 i…
Vulnerability class: Insecure Deserialization
EPSS: 0.061 (91.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Connectwise Screenconnect — versions <25.2.3
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2025-3935?
- CVE-2025-3935 is a high-severity vulnerability in Connectwise Screenconnect, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2025-04-25.
- How severe is CVE-2025-3935?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2025-3935 known to be exploited?
- Yes. CVE-2025-3935 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-06-02), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.