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Known exploited vulnerability

CVE-2025-3935

highCVSS 3.1 7.2In CISA KEVEPSS 3.6%Published · ConnectWise

The short answer

CVE-2025-3935 affects ConnectWise ScreenConnect and is rated high (CVSS 7.2). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-06-02: attackers are using it, so patch it first.

What it is

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.

Weakness: CWE-502.

Severity

7.2 high

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

Exploited (CISA KEV)

Yes, since Jun 2, 2025

Federal due date Jun 23, 2025

EPSS, next 30 days

3.6%

Higher than 90% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

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 products

ScreenConnect. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2025-3935 being exploited?

Yes. CISA added CVE-2025-3935 to its Known Exploited Vulnerabilities catalog on 2025-06-02, with a federal remediation due date of 2025-06-23.

How do I fix CVE-2025-3935?

CISA's 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.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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