ConnectWise ScreenConnect < 26.1 Authentication Bypass

critical Nessus Plugin ID 303452

Synopsis

A remote access server installed on the remote host is affected by an authentication bypass vulnerability.

Description

According to its version, the ConnectWise ScreenConnect remote access software installed on the remote host is prior to 26.1. It is, therefore, affected by an authentication bypass vulnerability:

- A condition in ScreenConnect may allow an actor with access to server-level cryptographic material used for authentication to obtain unauthorized access, including elevated privileges, in certain scenarios.
(CVE-2026-3564)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to ConnectWise ScreenConnect version 26.1 or later.

Plugin Details

Severity: Critical

ID: 303452

File Name: connectwise_screenconnect_26_1.nasl

Version: 1.1

Type: local

Agent: windows, macosx, unix

Family: Misc.

Published: 3/24/2026

Updated: 3/24/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 8.1

CVSS v2

Risk Factor: High

Base Score: 7.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-3564

CVSS v3

Risk Factor: Critical

Base Score: 9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Vulnerability Information

CPE: cpe:/a:connectwise:screenconnect

Required KB Items: installed_sw/ConnectWise ScreenConnect

Patch Publication Date: 3/17/2026

Vulnerability Publication Date: 3/17/2026

Reference Information

CVE: CVE-2026-3564

Detections

Analytics