Heap Buffer Overflow in FreeRDP Client Due to Malicious RDP Server

CVE-2026-44421

What is CVE-2026-44421?

FreeRDP, a widely-used free implementation of the Remote Desktop Protocol, is susceptible to a heap buffer overflow vulnerability. This issue allows a malicious RDP server to exploit the FreeRDP client by sending crafted RDPGFX PDUs, potentially leading to out-of-bounds heap writes. Specifically, the vulnerability lies in the gdi_CacheToSurface function, which improperly validates a destination rectangle but proceeds with an unsafe copy operation based on the original width and height values. As a result, this can result in client crashes or unauthorized code execution when RDPGFX is enabled. It is crucial for users to update to version 3.26.0 or later to mitigate this risk.

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