Red Hat Security Advisory: freerdp security update

Moderate

A flaw was found in FreeRDP. A remote attacker could exploit a use-after-free vulnerability in the `xf_SetWindowMinMaxInfo` function. This occurs when a freed window pointer is dereferenced because the main thread concurrently deletes a window while the Remote Desktop Protocol (RAIL) channel thread is still using the pointer. This flaw can lead to a denial of service.

CWE-825 - Expired Pointer Dereference

A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol. This double free vulnerability occurs during the cleanup process when a remote desktop session disconnects. Specifically, if a title allocation fails, a pointer to an application window is freed but not removed from a tracking table. Later, during disconnection, the same pointer is freed again, which can lead to a crash and result in a denial of service.

CWE-825 - Expired Pointer Dereference

A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol. The `Stream_EnsureCapacity` function can create an endless blocking loop, leading to a Denial of Service (DoS). This vulnerability can be exploited on 32-bit systems where the available physical memory is greater than or equal to the `SIZE_MAX` variable, potentially affecting both client and server implementations using FreeRDP.

CWE-190 - Integer Overflow or Wraparound

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.

CWE-787 - Out-of-bounds Write

A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol (RDP). A remote attacker can exploit a size_t underflow vulnerability in the IMA-ADPCM and MS-ADPCM audio decoders by sending specially crafted audio data over the RDPSND audio channel. This underflow leads to a heap-buffer-overflow write, which can result in a denial of service for the FreeRDP client.

CWE-191 - Integer Underflow (Wrap or Wraparound)

A division by zero flaw has been discovered in FreeRDP. This division by zero exists in the 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.

CWE-369 - Divide By Zero

An out of bounds read flaw has been discovered in FreeRDP. This out-of-bounds read exists in the MS-ADPCM and IMA-ADPCM decoders due to unchecked predictor and step_index values from input data. An attacker may be able to leverage this weakness to leak global data.

CWE-125 - Out-of-bounds Read

A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol. A remote attacker could exploit a vulnerability where pixel data from adjacent heap memory is rendered to the screen. This can lead to the disclosure of sensitive data to the attacker.

CWE-125 - Out-of-bounds Read