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.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.