# CVE-2025-3935: ScreenConnect Exposure to ASP.NET ViewState Code Injection

> CVE-2025-3935: ScreenConnect Exposure to ASP.NET ViewState Code Injection. CVSS 8.1 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2025-3935
Last updated: 2026-06-17T09:20:57Z

- Published: 2025-04-25 18:27 UTC · Updated: 2026-06-17 09:20 UTC · Assigner: ConnectWise
- CVSS: 8.1 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS: 3.5%, 89th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2025-06-02, federal due date 2025-06-23, ransomware use: Unknown
- CWE: CWE-502

## 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.

## CISA 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.

## Affected vendors and products

- ConnectWise: ScreenConnect

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-3935)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-3935)
- [https://www.connectwise.com/company/trust/advisories](https://www.connectwise.com/company/trust/advisories)
- [https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4](https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2025-3935 · Markdown: https://rewindex.com/cve/CVE-2025-3935.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-3935 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:01:37.635Z