How severe is CVE-2025-3935?

CVE-2025-3935 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-3935?

Affected package information for CVE-2025-3935 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2025-3935?

No fixed version has been published for CVE-2025-3935 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2025-3935 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-3935 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-3935?

CVE-2025-3935 has an EPSS (Exploit Prediction Scoring System) score of 6.1%, placing it in the 91th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is CVE-2025-3935 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-3935 (ConnectWise ScreenConnect Improper Authentication Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2025-06-02. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-06-23. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-3935?

CVE-2025-3935 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2025-3935?

CVE-2025-3935 affects connectwise screenconnect. Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2025-3935 published, and has it been updated?

CVE-2025-3935 was published on April 25, 2025 and was last updated on October 24, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-3935: Screenconnect Deserialization of Untrusted Data…

EPSS Exploitation Probability

via FIRST.org ↗

6.1%probability of exploitation in next 30 days

Lower Risk91th percentile-5.88%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Affected Products

1 product · 1 configurations

Application

screenconnectconnectwise

< 25.2.4

range

Frequently Asked Questions

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, bu

O3 Security · Impact-Aware SCA

Is CVE-2025-3935 in your stack?

O3 detects CVE-2025-3935 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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