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Vulnerabilities

Vulnerability · CVE-2026-3564

ConnectWise ScreenConnect Improper Verification of Cryptographic Signature

Published Mar 17, 2026 · catalog updated Jul 9, 2026 · ConnectWise ScreenConnect

Patch now

CVE-2026-3564 is in the CISA known-exploited catalog. Confirm ConnectWise ScreenConnect against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.0
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.29%
Remediation
Remediation guidance
Affected products
vendor ConnectWise ScreenConnect

A condition in the ScreenConnect server component may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios. ScreenConnect host and guest client agents are not independently affected by this CVE.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor ConnectWise ScreenConnectversion unspecified

How to fix CVE-2026-3564

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-3564 is in the CISA known-exploited catalog. Confirm ConnectWise ScreenConnect against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-347: Improper Verification of Cryptographic Signature. EPSS 0.29%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 17, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  2. Mar 17, 2026 · NIST NVD

    Detected

    A condition in the ScreenConnect server component may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios. ScreenConnect host and guest client agents are not independently affected by this CVE.

  3. Jul 9, 2026 · NIST NVD

    Updated

    A condition in the ScreenConnect server component may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios. ScreenConnect host and guest client agents are not independently affected by this CVE.

Sources

  • CVE.orgVulnerability recordCVE-2026-3564

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-3564

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-3564

    A condition in the ScreenConnect server component may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios. ScreenConnect host and guest client agents are not i

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-3564

    A condition in the ScreenConnect server component may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios. ScreenConnect host and guest client agents are not i

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.