CVE-2025-3935
ConnectWise ScreenConnect Improper Authentication - [Actively Exploited]
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.
INFO
Published Date :
April 25, 2025, 7:15 p.m.
Last Modified :
June 3, 2025, 8:38 p.m.
Source :
7d616e1a-3288-43b1-a0dd-0a65d3e70a49
Remotely Exploitable :
Yes !
Impact Score :
5.9
Exploitability Score :
2.2
CISA KEV (Known Exploited Vulnerabilities)
For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.
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.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4 ; https://nvd.nist.gov/vuln/detail/CVE-2025-3935
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-3935.
| URL | Resource |
|---|---|
| https://www.connectwise.com/company/trust/advisories | Vendor Advisory |
| https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4 | Vendor Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-3935 vulnerability anywhere in the article.
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The Hacker News
ConnectWise to Rotate ScreenConnect Code Signing Certificates Due to Security Risks
Vulnerability / Software Security ConnectWise has disclosed that it's planning to rotate the digital code signing certificates used to sign ScreenConnect, ConnectWise Automate, and ConnectWise remote ... Read more
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Dark Reading
ConnectWise to Rotate Code-Signing Certificates
Source: Stu Gray via Alamy Stock PhotoConnectWise this Friday will rotate all code-signing certificates for ScreenConnect, ConnectWise Automate, and ConnectWise RMM. While the software company recentl ... Read more
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The Register
US infrastructure could crumble under cyberattack, ex-NSA advisor warns
Infosec in Brief If a cyberattack hit critical infrastructure in the US, it would likely crumble, former deputy national security adviser and NSA cybersecurity director Anne Neuberger said last week. ... Read more
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BleepingComputer
CISA warns of ConnectWise ScreenConnect bug exploited in attacks
CISA is alerting federal agencies in the U.S. of hackers exploiting a recently patched ScreenConnect vulnerability that could lead to executing remote code on the server. The agency is warning that fo ... Read more
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TheCyberThrone
CISA Adds Five New Vulnerabilities to KEV Catalog
The Cybersecurity and Infrastructure Security Agency (CISA) has expanded its Known Exploited Vulnerabilities (KEV) Catalog, adding five new vulnerabilities that pose a high risk to federal agencies an ... Read more
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Daily CyberSecurity
CISA Adds 5 Actively Exploited Vulnerabilities to KEV Catalog: ASUS Routers, Craft CMS, and ConnectWise Targeted
The Cybersecurity and Infrastructure Security Agency (CISA) has added five new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, citing verified evidence of active exploitation in ... Read more
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Help Net Security
Attackers breached ConnectWise, compromised customer ScreenConnect instances
A suspected “sophisticated nation state actor” has compromised ScreenConnect cloud instances of a “very small number” of ConnectWise customers, the company has revealed on Wednesday. “We have not obse ... Read more
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TheCyberThrone
ConnectWise Cyberattack
In May 2025, ConnectWise, a major provider of IT automation and remote access tools, publicly confirmed a targeted cyberattack against its cloud-hosted ScreenConnect infrastructure. The attack has bee ... Read more
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The Register
ConnectWise customers get mysterious warning about 'sophisticated' nation-state hack
ConnectWise has brought in the big guns to investigate a "sophisticated nation state actor" that broke into its IT environment and then breached some of its customers. In a May 28 advisory, the IT man ... Read more
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Cyber Security News
Critical ScreenConnect Vulnerability Let Attackers Inject Malicious Code
ConnectWise has released an urgent security patch for its ScreenConnect remote access software to address a serious vulnerability that could allow attackers to execute malicious code on affected syste ... Read more
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Daily CyberSecurity
ConnectWise Patches Critical ViewState RCE Vulnerability in ScreenConnect
ConnectWise has issued an important security bulletin addressing a critical code injection vulnerability in ScreenConnect versions 25.2.3 and earlier. Tracked as CVE-2025-3935 (CVSS 81), the flaw invo ... Read more
The following table lists the changes that have been made to the
CVE-2025-3935 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Jun. 03, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:a:connectwise:screenconnect:*:*:*:*:*:*:*:* versions up to (excluding) 25.2.4 Added Reference Type ConnectWise: https://www.connectwise.com/company/trust/advisories Types: Vendor Advisory Added Reference Type ConnectWise: https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4 Types: Vendor Advisory -
CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725
Jun. 03, 2025
Action Type Old Value New Value Added Date Added 2025-06-02 Added Due Date 2025-06-23 Added 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. Added Vulnerability Name ConnectWise ScreenConnect Improper Authentication Vulnerability -
New CVE Received by 7d616e1a-3288-43b1-a0dd-0a65d3e70a49
Apr. 25, 2025
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-287 Added Reference https://www.connectwise.com/company/trust/advisories Added Reference https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-3935 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-3935
weaknesses.