CVE-2023-40574 in FreeRDP
Summary
by MITRE • 09/01/2023
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Affected versions are subject to an Out-Of-Bounds Write in the `writePixelBGRX` function. This issue is likely down to incorrect calculations of the `nHeight` and `srcStep` variables. This issue has been addressed in version 3.0.0-beta3. Users are advised to upgrade. There are no known workarounds for this issue.
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Analysis
by VulDB Data Team • 03/13/2026
The vulnerability CVE-2023-40574 represents a critical out-of-bounds write condition within FreeRDP's `writePixelBGRX` function that could enable remote code execution or system compromise. This issue affects versions of FreeRDP prior to 3.0.0-beta3 and stems from improper calculation of memory access parameters, specifically the `nHeight` and `srcStep` variables that govern pixel data processing. The flaw exists in the RDP client implementation that handles graphics rendering for remote desktop connections, making it particularly dangerous in environments where remote access is extensively used. The vulnerability is classified as a buffer overflow condition that occurs when the application attempts to write data beyond the allocated memory boundaries, potentially allowing attackers to overwrite adjacent memory locations with malicious content.
FreeRDP serves as a widely adopted open-source implementation of Microsoft's Remote Desktop Protocol, used extensively in enterprise environments, cloud computing infrastructures, and remote access solutions across various operating systems including Linux, Windows, and macOS. The `writePixelBGRX` function specifically handles the processing of pixel data in BGRX format, which is fundamental to graphics rendering in remote desktop sessions. When an attacker can manipulate the parameters controlling `nHeight` and `srcStep`, they can cause the application to write beyond the intended memory allocation, potentially corrupting critical data structures or executing arbitrary code. This vulnerability falls under CWE-787 Out-of-bounds Write, which is categorized as a high-severity weakness in the Common Weakness Enumeration catalog. The flaw demonstrates poor input validation and memory management practices, where the application fails to properly verify the bounds of memory operations before executing them.
The operational impact of this vulnerability extends across numerous attack vectors since FreeRDP is integrated into various remote access solutions, virtual desktop infrastructures, and enterprise security tools. Attackers could exploit this vulnerability by crafting specially malformed RDP packets or graphics data that triggers the flawed memory access pattern during normal remote desktop session processing. This could result in complete system compromise, data exfiltration, or denial of service conditions affecting remote desktop services. The vulnerability's exploitation potential is heightened by the fact that it occurs during normal graphics processing operations, meaning that simply connecting to a vulnerable system or participating in a remote desktop session could trigger the exploit. Organizations using FreeRDP in production environments face significant risk, particularly those with exposed RDP services or those implementing remote work solutions that rely on this protocol implementation.
Mitigation strategies for CVE-2023-40574 center exclusively on upgrading to FreeRDP version 3.0.0-beta3 or later, as no effective workarounds exist for this particular vulnerability. Security administrators should prioritize patching affected systems immediately, particularly those running FreeRDP in environments where remote desktop access is enabled or where the software is integrated into critical infrastructure components. The vulnerability's nature as a memory corruption issue makes it particularly challenging to defend against through traditional network security measures, as the exploit can occur during legitimate RDP session establishment and processing. Organizations should implement comprehensive vulnerability management processes that include regular security assessments of remote access solutions, monitoring for exploitation attempts, and maintaining up-to-date security patches across all systems utilizing FreeRDP. This vulnerability also underscores the importance of input validation and memory safety practices in network protocol implementations, aligning with ATT&CK technique T1059.007 for execution through remote services and T1566 for social engineering via remote access tools. Given the nature of RDP implementations and their integration into enterprise security architectures, this vulnerability represents a significant concern for organizations implementing zero-trust security models where remote access controls are paramount.