CVE-2026-29775

A heap based buffer overflow flaw has been discovered in FreeRDP. This client-side heap out-of-bounds read/write occurs in FreeRDP's bitmap cache subsystem due to an off-by-one boundary check in bitmap_cache_put. A malicious server can send a CACHE_BITMAP_ORDER (Rev1) with cacheId equal to maxCells, bypassing the guard and accessing cells[] one element past the allocated array. A malicious server can trigger a client-side heap out-of-bounds access (READ of 4 bytes, followed by potential WRITE of a pointer) on the bitmap cache cells array, causing a crash (DoS) and heap corruption. The off-by-one accesses cells[maxCells] which reads from and writes to adjacent heap memory, potentially enabling pointer overwrite for code execution depending on heap layout.