CVE-2025-3935: ConnectWise ScreenConnect Improper Authentication Vulnerability

CISA Known Exploited Vulnerability (KEV)

Description

ConnectWise ScreenConnect contains an improper authentication vulnerability. This vulnerability could allow a ViewState code injection attack, which could allow remote code execution if machine keys are compromised.

Required action (CISA)

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

Notes

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

Weakness behind it

CISA records this vulnerability as an instance of CWE-287. From there the chain continues into CAPEC attack patterns and ATT&CK techniques, all inside this corpus.

References

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-3935
• KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog