Magna5 Cybersecurity Advisory: Critical Windows Remote Desktop Services Vulnerability

Magna5 is sharing this advisory regarding CVE-2026-69525, a critical remote code execution vulnerability affecting Microsoft Windows Remote Desktop Services (RDS).

What is it?

CVE-2026-69525 is a critical Remote Desktop Services remote code execution vulnerability. An unauthenticated attacker could potentially exploit the vulnerability over a network. Systems with internet-facing or externally reachable RDP/RDS services should be prioritized for review and remediation.

Microsoft addressed this vulnerability in the September 2026 security updates. Separately, public reports indicate that some Windows Server 2019, 2022, and 2025 systems may experience Remote Desktop Services connectivity or functionality issues after installing these updates. Accordingly, RDS-dependent systems should be patched through a controlled and validated rollout process.

What is Magna5 doing?

For customers enrolled in Magna5 Patch Management services, Magna5 is reviewing the applicable Microsoft updates and planning deployment through our standard patch-management process. For RDS-dependent or otherwise critical systems, deployments may be staged to help validate service functionality and reduce operational risk.

Magna5 is also monitoring managed environments for potential exposure and suspicious activity related to this vulnerability using available cybersecurity tools and service visibility. If we identify a potentially affected system or concerning activity, we will follow our standard notification and escalation procedures.

Required customer action

Customers with Magna5 Patch Management: No immediate patching action is required unless contacted by Magna5. We are reviewing and planning deployment of the applicable updates. Customers should notify Magna5 of any business-critical RDS servers, maintenance constraints, or special validation requirements.

Customers without Magna5 Patch Management: Customer action is required. Please review affected systems and apply Microsoft’s security updates using a staged, validated deployment process.

For all environments using RDP or RDS, Magna5 recommends:

• Prioritize internet-facing or externally reachable RDP/RDS systems.
• Test updates before broad deployment where possible.
• Confirm alternate administrative access, such as console, hypervisor, VPN, or out-of-band access, before patching critical servers.
• Validate RDP/RDS connectivity and service functionality after installation and reboot.
• Restrict RDP/RDS access to trusted networks or VPN access where possible.
• Monitor for unusual RDP/RDS logon activity or unexpected service behavior.

Magna5 does not recommend broadly uninstalling security updates, as doing so may reintroduce exposure to vulnerabilities addressed by the September 2026 updates.

For assistance or if you believe your environment may be affected, please contact cybersecurity@magna5.com.

Additional information: National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2026-69525

BleepingComputer: https://www.bleepingcomputer.com/news/microsoft/september-windows-server-updates-break-remote-desktop-services/