Historical catalog analysis: CISA added this entry on June 02, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.
What the vulnerability is
CVE-2025-3935 is an improper authentication vulnerability (CWE-287) identified in ConnectWise ScreenConnect. The flaw could allow an attacker to perform a ViewState code injection attack. If the system’s machine keys are compromised, this vulnerability could lead to remote code execution (RCE).
Exposure and applicability
ScreenConnect is a remote monitoring and management tool frequently utilized by healthcare IT departments and Business Associates to maintain clinical systems and provide technical support. Because these tools often possess high-level administrative privileges across a network, an RCE vulnerability represents a significant risk to the confidentiality of electronic Protected Health Information (ePHI) and the overall continuity of patient care.
Organizations using ScreenConnect—whether managed internally or through a third-party provider—should determine if their current deployment is susceptible to this flaw. While CISA added this to its Known Exploited Vulnerabilities (KEV) catalog on June 2, 2025, the risk applies to any environment where the tool is exposed and machine keys are not sufficiently protected.
Remediation priorities
Based on our analysis of the vulnerability, healthcare security leaders should prioritize the following actions:
- Vendor Mitigation Application: The primary priority is to apply the mitigations provided by ConnectWise. This is a preventative control intended to stop initial unauthorized access via this specific vector.
- Business Associate Audit: For providers relying on managed service providers (MSPs), verify that the partner has applied the necessary patches or mitigations across all instances managing the provider’s environment.
- Machine Key Review: Since the RCE potential is tied to the compromise of machine keys, organizations should evaluate the security and rotation policies for these keys as a layer of defense-in-depth to limit the impact of an authentication bypass.
- Service Evaluation: If mitigations are unavailable or cannot be applied due to legacy system constraints, the organization should consider discontinuing the use of the product to eliminate the attack surface.
How to validate remediation
To verify that exposure has been reduced, IT and clinical engineering teams can employ the following methods:
- Version Verification: Confirm that the installed version of ScreenConnect matches the patched or mitigated versions specified in the vendor’s security bulletin.
- Configuration Audit: Review system logs and configuration files to ensure that mitigations are active and that machine keys have been handled according to current security best practices.
- Vendor Attestation: For cloud-hosted services, request formal confirmation from the service provider that BOD 22-01 guidance or equivalent vendor mitigations have been implemented.
Limits and open questions
It is important to note that applying a patch may not be a definitive guarantee of security if machine keys were compromised prior to the update. The source does not specify whether this vulnerability has been utilized in known ransomware campaigns, leaving the current threat landscape for this specific CVE partially unknown. Additionally, while CISA established a remediation deadline of June 23, 2025, for federal agencies, this date serves as a risk indicator rather than a legal mandate for private healthcare entities.
Source and editorial note
CVE-2025-3935: ConnectWise ScreenConnect Improper Authentication Vulnerability · Source date: June 02, 2025 · Retrieved August 31, 2026.
Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.
Archive date: June 05, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 10, 2026 at 00:48 UTC.
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