Threats / ConnectWise / CVE-2025-3935
CVE-2025-3935
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
ConnectWise ScreenConnect vulnerability
ConnectWise ScreenConnect contains an improper authentication vulnerability allowing ViewState code injection and remote code execution when machine keys are compromised.
Verdict
Today item — known-exploited.
An unauthenticated attacker can inject malicious code through ViewState manipulation in ScreenConnect, leading to remote code execution if the application's machine keys are known or accessible. This vulnerability is actively exploited in the wild.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
6 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-06-02).
Probability (EPSS)
EPSS 0.03348 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: ConnectWise, ScreenConnect. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-287 Improper Authentication — weakness family: Authentication.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify that ScreenConnect uses predictable or exposed machine keys for ViewState cryptographic operations.
Business
Sensitive cryptographic material is inadequately protected, creating a foundational security gap.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious ViewState payload and inject it into the application without authentication.
Business
Authentication controls fail to prevent unauthorized code submission to the application.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute arbitrary code on the ScreenConnect server through deserialization of my injected payload.
Business
The organization loses control of affected systems and faces potential data theft, lateral movement, or service disruption.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by ConnectWiseCNA
Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.