CVE-2026-80077 in Remote Desktop Client
Summary
by MITRE • 09/09/2026
Heap-based buffer overflow in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Remote Desktop Client, specifically manifesting as a heap-based buffer overflow. This type of memory corruption error occurs when a program writes data beyond the allocated boundaries of a buffer located in the heap segment of computer memory. In the context of network-facing applications like the Remote Desktop Protocol (RDP) client, this flaw is particularly severe because it can be triggered remotely by an unauthenticated attacker. The underlying technical mechanism involves improper handling of input data received over the network. When the client processes specific malformed packets or specially crafted RDP messages, it fails to adequately validate the length and content of the incoming data before copying it into a pre-allocated memory buffer. This lack of rigorous boundary checking allows an external actor to overwrite adjacent memory locations on the heap with arbitrary data.
The operational impact of this vulnerability is profound, as successful exploitation grants an unauthorized attacker the ability to execute arbitrary code on the target system. By carefully crafting the overflow payload, an attacker can manipulate function pointers or exception handlers within the heap structure. This manipulation redirects the execution flow of the vulnerable application, allowing the injection and subsequent running of malicious shellcode. Consequently, this leads to a complete compromise of the affected host. The attacker gains the same user rights as the local user executing the Remote Desktop Client. If that user possesses administrative privileges on the target system, the attacker can take full control of the machine, install programs, view, change, or delete data, and create new accounts with unrestricted access. This effectively bypasses standard security boundaries established by operating systems like Microsoft Windows.
From a classification perspective, this vulnerability aligns closely with CWE-122, which denotes Heap-based Buffer Overflow, indicating that the root cause is insufficient validation of input size relative to buffer capacity in dynamically allocated memory. Furthermore, given its network-exploitable nature and potential for remote code execution without user interaction beyond initiating or receiving a connection, it maps directly to MITRE ATT&CK technique T1203, which covers Exploitation for Client Execution. This classification highlights the threat actor's strategy of leveraging client-side software vulnerabilities as an initial access vector rather than targeting server infrastructure directly. The ability to execute code remotely makes this vulnerability a high-priority target for automated scanning tools and advanced persistent threats seeking lateral movement within enterprise networks.
Mitigation strategies must address both immediate remediation and long-term architectural resilience. The primary defense is the timely application of vendor-provided security patches that correct the input validation logic within the Remote Desktop Client binaries. Organizations should prioritize patching all endpoints running vulnerable versions of the client software, especially those exposed to untrusted networks or used by users who frequently connect to external systems. In addition to patching, network segmentation plays a crucial role in limiting exposure. Restricting RDP traffic through firewalls and ensuring that only authorized IP addresses can initiate connections reduces the attack surface significantly. Implementing multi-factor authentication for remote desktop sessions adds an additional layer of security, although it does not directly prevent exploitation of this specific memory corruption flaw if the client is already compromised during the handshake or data processing phase. Continuous monitoring for anomalous network traffic patterns associated with RDP protocol anomalies can also aid in early detection of attempted exploits before successful code execution occurs.