CVE-2025-27480 in Windows
Summary
by MITRE • 04/08/2025
Use after free in Remote Desktop Gateway Service allows an unauthorized attacker to execute code over a network.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/09/2026
This vulnerability represents a critical use-after-free flaw in the Remote Desktop Gateway service that enables remote code execution by unauthorized attackers. The vulnerability occurs when the service improperly handles memory management during processing of remote desktop connections, creating a scenario where freed memory blocks are accessed after being reallocated. This memory corruption issue stems from inadequate validation of input parameters and failure to properly manage object lifecycles within the gateway service implementation. The flaw exists at the protocol processing layer where the service handles incoming connection requests and authentication tokens, making it particularly dangerous as it can be exploited without requiring authentication credentials. Attackers can leverage this vulnerability by crafting malicious connection requests that trigger the use-after-free condition, potentially leading to arbitrary code execution with elevated privileges. The vulnerability aligns with CWE-416 which specifically addresses use-after-free errors in memory management, and maps to ATT&CK technique T1210 for exploitation of remote services. The Remote Desktop Gateway service operates on standard ports 3389 and 443, making it accessible over networks and increasing the attack surface. When exploited, this vulnerability can allow attackers to establish persistent access to target networks, escalate privileges, and potentially move laterally throughout the infrastructure. The impact extends beyond immediate code execution as it can facilitate complete system compromise and data exfiltration. Organizations running affected versions of Windows Server and Remote Desktop Services are particularly vulnerable, with the risk being highest when the gateway service is exposed to untrusted networks. The vulnerability demonstrates a fundamental flaw in the service's memory handling mechanisms and highlights the importance of proper input validation and resource management in network services. Security researchers have identified that the flaw manifests when the service processes malformed connection requests or authentication parameters that cause memory deallocation followed by subsequent access. This type of vulnerability is particularly challenging to detect and remediate as it often requires deep system-level analysis and memory debugging to identify the precise conditions that trigger the exploit. The use-after-free condition creates a predictable memory corruption pattern that attackers can reliably exploit across multiple Windows Server versions, making it a preferred target for automated exploitation tools. The vulnerability's network accessibility means that attackers can leverage it from external networks without requiring physical access or prior authentication, significantly increasing the attack surface. Organizations should consider implementing network segmentation to restrict access to Remote Desktop services and deploy intrusion detection systems to monitor for exploitation attempts. The flaw underscores the necessity of regular security updates and patch management programs, as Microsoft has released security patches addressing this specific vulnerability. Mitigation strategies should include disabling unnecessary Remote Desktop services, implementing strict firewall rules, and monitoring for anomalous connection patterns that may indicate exploitation attempts. The vulnerability also emphasizes the importance of application security testing including memory safety analysis and fuzzing techniques to identify similar flaws in network services. Proper code review practices and adherence to secure coding standards can help prevent such memory management errors in future implementations. Organizations should also consider implementing additional security controls such as multi-factor authentication and privileged access management to reduce the potential impact of successful exploitation attempts. The vulnerability's classification as a remote code execution flaw makes it particularly concerning for enterprise environments where Remote Desktop services are commonly deployed for administrative access and remote work scenarios.