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) affecting ConnectWise ScreenConnect. The flaw allows for a ViewState code injection attack. According to source data, this specific path can lead to remote code execution (RCE), provided that the attacker has already compromised the system’s machine keys.
Exposure and applicability
This vulnerability applies to organizations deploying ConnectWise ScreenConnect. The risk of RCE is conditional; it is not a standalone entry point but requires the prerequisite compromise of machine keys to facilitate the ViewState injection. Infrastructure owners should identify all instances of ScreenConnect within their environment to determine if they are running versions susceptible to this authentication failure.
Remediation priorities
Based on our analysis, vulnerability management teams should prioritize the following actions:
- Apply Vendor Patches: The primary corrective action is to implement mitigations as specified in the ConnectWise security bulletin (screenconnect-security-patch-2025.4). This should be treated as a high priority given its inclusion in CISA’s Known Exploited Vulnerabilities (KEV) catalog.
- Evaluate Machine Key Integrity: Because RCE depends on compromised machine keys, defenders should investigate whether these keys have been exposed or leaked, as this significantly increases the exploitability of the ViewState injection.
- Decommission Unpatchable Assets: If mitigations are unavailable for a specific deployment, our analysis suggests discontinuing use of the product to eliminate the exposure path.
How to validate remediation
Verification must go beyond confirming a version number. To ensure exposure is reduced, defenders should:
* Verify Patch Application: Confirm that the vendor-supplied security updates are active across all ScreenConnect nodes.
* Audit Key Rotation: If there is any suspicion that machine keys were compromised prior to patching, rotating those keys is a necessary step to invalidate the prerequisite for the RCE path.
Confirmation of a version update alone does not prove that the environment is secure if the underlying machine keys remain compromised and accessible to an attacker.
Limits and open questions
There are remaining uncertainties regarding this vulnerability. It is currently unknown whether this flaw has been utilized in known ransomware campaigns. Additionally, while CISA has established a remediation deadline of June 23, 2025, for federal agencies, this date serves as a risk indicator rather than a mandatory requirement for private sector organizations. Residual risk remains if machine keys are compromised via other vectors, potentially allowing an attacker to leverage the ViewState injection despite general authentication controls.
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 13, 2026 at 00:24 UTC.
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