CVE-2026-23531 — Heap-based Buffer Overflow in Freerdp

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, in ClearCodec, when `glyphData` is present, `clear_decompress` calls `freerdp_image_copy_no_overlap` without validating the destination rectangle, allowing an out-of-bounds read/write via crafted RDPGFX surface updates. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surroundin…