Freerdp Freerdp vulnerabilities

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, division by zero in MS-ADPCM and IMA-ADPCM decoders when nBlockAlign is 0, leading to a crash. In libfreerdp/codec/dsp.c, both ADPCM decoders use size % block_size where block_size = context->common.format.nBlockAlign. The nBlockAlign value comes from the Server Audio Formats PDU on the RDPSND channel. The value 0 is not validated anywhere before reaching the decoder. When nBlockAlign = 0, the modulo operation causes a SIGFPE (floating point exception) crash. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a 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. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a client-side heap buffer overflow occurs in the FreeRDP client's AVC420/AVC444 YUV-to-RGB conversion path due to missing horizontal bounds validation of H.264 metablock regionRects coordinates. In yuv.c, the clamp() function (line 347) only validates top/bottom against the surface/YUV height, but never checks left/right against the surface width. When avc420_yuv_to_rgb (line 67) computes destination and source pointers using rect->left, it performs unchecked pointer arithmetic that can reach far beyond the allocated surface buffer. A malicious server sends a WIRE_TO_SURFACE_PDU_1 with AVC420 codec containing a regionRects entry where left greatly exceeds the surface width (e.g., left=60000 on a 128px surface). The H.264 bitstream decodes successfully, then yuv420_process_work_callback calls avc420_yuv_to_rgb which computes pDstPoint = pDstData + rect->top * nDstStep + rect->left * 4, writing 16-byte SSE vectors 1888+ bytes past the allocated heap region. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, the function `Stream_EnsureCapacity` can create an endless blocking loop. This may affect all client and server implementations using `FreeRDP`. For practical exploitation this will only work on 32bit systems where the available physical memory is `>= SIZE_MAX`. Version 3.23.0 contains a patch. No known workarounds are available.

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.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `rail_window_free` dereferences a freed `xfAppWindow` pointer during `HashTable_Free` cleanup because `xf_rail_window_common` calls `free(appWindow)` on title allocation failure without first removing the entry from the `railWindows` hash table, leaving a dangling pointer that is freed again on disconnect. Version 3.23.0 fixes the vulnerability.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, in the RLE planar decode path, `planar_decompress_plane_rle()` writes into `pDstData` at `((nYDst+y) * nDstStep) + (4*nXDst) + nChannel` without verifying that `(nYDst+nSrcHeight)` fits in the destination height or that `(nXDst+nSrcWidth)` fits in the destination stride. When `TempFormat != DstFormat`, `pDstData` becomes `planar->pTempData` (sized for the desktop), while `nYDst` is only validated against the **surface** by `is_within_surface()`. A malicious RDP server can exploit this to perform a heap out-of-bounds write with attacker-controlled offset and pixel data on any connecting FreeRDP client. The OOB write reaches up to 132,096 bytes past the temp buffer end, and on the brk heap (desktop ≤ 128×128), an adjacent `NSC_CONTEXT` struct's `decode` function pointer is overwritten with attacker-controlled pixel data — control-flow–relevant corruption (function pointer overwritten) demonstrated under deterministic heap layout (`nsc->decode = 0xFF414141FF414141`). Version 3.23.0 fixes the vulnerability.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, a malicious RDP server can trigger a heap buffer overflow in FreeRDP clients using the GDI surface pipeline (e.g., `xfreerdp`) by sending an RDPGFX ClearCodec surface command with an out-of-bounds destination rectangle. The `gdi_SurfaceCommand_ClearCodec()` handler does not call `is_within_surface()` to validate the command rectangle against the destination surface dimensions, allowing attacker-controlled `cmd->left`/`cmd->top` (and subcodec rectangle offsets) to reach image copy routines that write into `surface->data` without bounds enforcement. The OOB write corrupts an adjacent `gdiGfxSurface` struct's `codecs*` pointer with attacker-controlled pixel data, and corruption of `codecs*` is sufficient to reach an indirect function pointer call (`NSC_CONTEXT.decode` at `nsc.c:500`) on a subsequent codec command — full instruction pointer (RIP) control demonstrated in exploitability harness. Users should upgrade to version 3.23.0 to receive a patch.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_rail_server_local_move_size` dereferences a freed `xfAppWindow` pointer because `xf_rail_get_window` returns an unprotected pointer from the `railWindows` hash table, and the main thread can concurrently delete the window (via a window delete order) while the RAIL channel thread is still using the pointer. Version 3.23.0 fixes the issue.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_rail_server_execute_result` indexes the global `error_code_names[]` array (7 elements, indices 0–6) with an unchecked `execResult->execResult` value received from the server, allowing an out-of-bounds read when the server sends an `execResult` value of 7 or greater. Version 3.23.0 fixes the issue.

FreeRDP is a free implementation of the Remote Desktop Protocol. Versions on the 2.x branch prior to to 2.11.8 and on the 3.x branch prior to 3.23.0 have an out-of-bounds read vulnerability in the FreeRDP client's RDPGFX channel that allows a malicious RDP server to read uninitialized heap memory by sending a crafted WIRE_TO_SURFACE_2 PDU with a `bitmapDataLength` value larger than the actual data in the packet. This can lead to information disclosure or client crashes when a user connects to a malicious server. Versions 2.11.8 and 3.23.0 fix the issue.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.22.0, the RDPSND async playback thread can process queued PDUs after the channel is closed and internal state is freed, leading to a use after free in rdpsnd_treat_wave. This vulnerability is fixed in 3.22.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. ainput_send_input_event caches channel_callback in a local variable and later uses it without synchronization; a concurrent channel close can free or reinitialize the callback, leading to a use after free. Prior to 3.22.0, This vulnerability is fixed in 3.22.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.22.0, audin_server_recv_formats frees an incorrect number of audio formats on parse failure (i + i), leading to out-of-bounds access in audio_formats_free. This vulnerability is fixed in 3.22.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.22.0, aAsynchronous bulk transfer completions can use a freed channel callback after URBDRC channel close, leading to a use after free in urb_write_completion. This vulnerability is fixed in 3.22.0.