CVE-2025-3935 | ScreenConnect Exposure to ASP.NET ViewState Code Injection

Exp

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.

Published: 2025-04-25 Last update: 2026-06-17 Assigner: 7d616e1a-3288-43b1-a0dd-0a65d3e70a49 Source: 7d616e1a-3288-43b1-a0dd-0a65d3e70a49
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-3935 is rated Critical Active Threat (85.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.35%). CISA KEV confirms active exploitation (added 2025-06-02) affecting ConnectWise / ScreenConnect. a weakness (CWE-502) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2025-3935

Name: ConnectWise ScreenConnect Improper Authentication Vulnerability · CISA KEV detail

Exploit added: 2025-06-02

Action due: 2025-06-23

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.

Exploit prediction scoring system (EPSS) score for CVE-2025-3935

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 6.15% 3.35% -2.80%
2 2026-06-03 12.03% 6.15% -5.88%
3 2026-05-13 — 12.03% —

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-3935

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 7d616e1a-3288-43b1-a0dd-0a65d3e70a49
7.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.2 5.9 [email protected]

Weakness enumeration for CVE-2025-3935

Affected software / configurations for CVE-2025-3935

Vendor Product Version Raw CPE
connectwise screenconnect < 25.2.4 cpe:2.3:a:connectwise:screenconnect:*:*:*:*:*:*:*:*

References for CVE-2025-3935

cvelogic Threat Intelligence