In May 2025, Microsoft addressed several critical vulnerabilities within its Windows Remote Desktop services, notably CVE-2025-29966 and CVE-2025-29967. These flaws could enable attackers to execute malicious code remotely, posing significant risks to system security.
Understanding the Vulnerabilities
CVE-2025-29966 and CVE-2025-29967 are heap-based buffer overflow vulnerabilities found in the Remote Desktop Client and Gateway Service, respectively. These vulnerabilities allow unauthorized attackers to execute arbitrary code over a network. Specifically, an attacker controlling a Remote Desktop Server could exploit these flaws to trigger remote code execution on a client machine when the victim connects using a vulnerable Remote Desktop Client.
Technical Details
These vulnerabilities are classified under CWE-122: Heap-based Buffer Overflow. This classification indicates that the flaws involve improper handling of memory allocation, leading to potential code execution. Both vulnerabilities have received Critical severity ratings with high CVSS scores, reflecting their potential impact on affected systems.
Affected Systems
The vulnerabilities impact multiple versions of Windows operating systems that utilize Remote Desktop services. While Microsoft has not reported active exploitation of these specific flaws, the company has assessed them with an Exploitation Less Likely rating. However, given the history of similar vulnerabilities being targeted, the potential for exploitation remains a concern.
Historical Context
Remote Desktop vulnerabilities have been prime targets for attackers in the past. For instance, the BlueKeep vulnerability (CVE-2019-0708) discovered in 2019 allowed for remote code execution and was considered wormable, meaning it could propagate between vulnerable systems without user interaction. This underscores the importance of promptly addressing such vulnerabilities to prevent widespread exploitation.
Mitigation Measures
To protect systems from potential exploits, it is crucial to apply the patches provided in Microsoft’s May 2025 Patch Tuesday update. These updates are available through Windows Update, Windows Server Update Services (WSUS), and the Microsoft Update Catalog. For systems that cannot be immediately patched, limiting Remote Desktop connections to trusted servers and implementing additional network security measures are recommended to restrict potential attack vectors.
Conclusion
The discovery and patching of CVE-2025-29966 and CVE-2025-29967 highlight the ongoing need for vigilance in cybersecurity practices. Organizations and individual users must prioritize applying security updates and implementing robust security measures to safeguard against potential threats.
