CVE-2026-27950 in FreeRDP
Summary
by MITRE • 02/26/2026
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, the fix for the heap-use-after-free described in CVE-2026-24680 is incomplete. While the vulnerable execution flow referenced in the advisory exists in the SDL2 implementation, the fix appears to have been applied only to the SDL3 code path. In the SDL2 implementation, the pointer is not nulled after free. This creates a situation where the advisory suggests the vulnerability is fully resolved, while builds or environments still using SDL2 may retain the vulnerable logic. A complete fix is available in version 3.23.0.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability described in CVE-2026-27950 affects FreeRDP, a widely-used open-source implementation of Microsoft's Remote Desktop Protocol that enables remote desktop connections across various platforms. This issue represents a critical heap-use-after-free vulnerability that emerged from an incomplete security patch addressing a previously identified flaw. The vulnerability specifically impacts users operating FreeRDP versions prior to 3.23.0, creating a scenario where the security remediation appears complete but remains partially effective due to the incomplete application of fixes across different code implementations.
The technical flaw manifests in the SDL2 implementation of FreeRDP where a pointer is not properly nulled after memory deallocation occurs. This heap-use-after-free condition creates a dangerous state where freed memory can be accessed and potentially exploited by malicious actors. The vulnerability exists within the same execution flow that was previously documented in CVE-2026-24680, indicating a regression or incomplete remediation process. While the SDL3 code path received proper treatment with the necessary pointer nullification after free operations, the SDL2 implementation retained the original problematic behavior, creating a false sense of security for users who may be operating in SDL2 environments.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can potentially enable remote code execution or denial-of-service conditions within the affected FreeRDP installations. Attackers could exploit this condition to manipulate freed memory locations, potentially leading to arbitrary code execution on systems running vulnerable FreeRDP versions. The issue particularly affects organizations that rely on SDL2-based implementations for their remote desktop infrastructure, as these deployments remain vulnerable despite the apparent resolution of the primary vulnerability. This creates a fragmented security landscape where patch management efforts may appear complete but leave critical attack surfaces exposed in specific implementation variants.
Organizations should immediately upgrade to FreeRDP version 3.23.0 or later to ensure complete remediation of this vulnerability. System administrators must verify their FreeRDP installations are not utilizing the SDL2 implementation, or ensure that all code paths receive proper patching. The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions, and represents a clear violation of secure coding practices that should prevent memory access after deallocation. From an attack surface perspective, this vulnerability maps to ATT&CK technique T1059.007 for remote code execution and T1499.004 for denial-of-service attacks, making it particularly concerning for enterprise environments relying on remote desktop connectivity. The incomplete patch application also highlights the importance of thorough regression testing and comprehensive code path verification when implementing security fixes to prevent similar issues in future releases.