Security readout for executives and security teams
Plain-English summary
CVE-2026-3564 affects ConnectWise ScreenConnect servers before version 26.1. If an attacker obtains server-level cryptographic material used for authentication, they may gain unauthorized access and possibly elevated privileges. The client agents are not independently affected, but compromised server trust material can create serious business risk.
Executive priority
Prioritize this for any organization operating ScreenConnect servers. The vulnerability is critical because stolen server trust material could support unauthorized privileged access, even though active exploitation is not confirmed in the supplied sources.
Technical view
The issue is a ScreenConnect server-side cryptographic validation/authentication weakness categorized as CWE-347. The CVSS 3.1 score is 9.0 with network attack vector, high attack complexity, no privileges, no user interaction, scope change, and high confidentiality, integrity, and availability impact.
Likely exposure
Organizations running ScreenConnect server versions earlier than 26.1 are potentially exposed. Host and guest client agents alone are not listed as independently affected by this CVE.
Exploitation context
The supplied sources do not show CISA KEV listing or confirmed active exploitation. Exploitation appears dependent on attacker access to server-level cryptographic material, which raises impact but may limit opportunistic abuse.
Researcher notes
Evidence is limited to the CVE record and ConnectWise bulletin reference. Key unknowns include exact failure conditions, rotation requirements, and detection indicators. Do not assume exploit availability without additional public evidence.
Mitigation direction
- Upgrade ScreenConnect server deployments to version 26.1 or later.
- Review the ConnectWise bulletin for current vendor remediation guidance.
- Treat exposed server-level cryptographic material as a credential compromise.
- Restrict and audit access to server keys, backups, and configuration material.
Validation and detection
- Inventory all ScreenConnect server versions and flag anything before 26.1.
- Confirm client agents are not counted as independently affected assets.
- Review access paths to server-level cryptographic material.
- Check authentication and administrative logs for unexplained privileged access.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-347: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-3564 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H2.26ConnectWiseVulnerability scoring details
Base CVSS 3.1 score
9CriticalVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://www.connectwise.com/company/trust/security-bulletins/2026-03-17-screenconnect-bulletinCVE reference, ConnectWise
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Verification of Cryptographic Signature
Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.