CVE-2026-110837 in FreeRDP
Summary
by MITRE • 10/15/2026
FreeRDP 2.0.0 before 3.32.0, when built with WITH_LAME=ON and WITH_DSP_FFMPEG=OFF, has a heap-based buffer overflow in freerdp_dsp_decode_mp3 because the right-channel PCM pointer is offset by a byte count treated as short elements. A malicious RDP server can send MP3 audio over rdpsnd so decoded samples cross the heap allocation, crashing the client.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in FreeRDP versions prior to 3.32.0 represents a critical memory safety flaw within the multimedia processing subsystem, specifically affecting configurations where LAME support is enabled while FFmpeg DSP support is disabled. This specific build configuration isolates the MP3 decoding logic to rely on external libraries that interact with internal buffer management routines in ways that expose a fundamental arithmetic error during audio stream processing. The core of the issue resides within the freerdp_dsp_decode_mp3 function, which handles the conversion of compressed MP3 data into raw Pulse Code Modulation PCM samples for playback or further processing by the remote desktop client application.
The technical root cause is classified as a heap-based buffer overflow resulting from an incorrect calculation of memory offsets during channel separation. When decoding stereo audio streams, the decoder must allocate separate buffers for left and right channels to ensure proper spatial audio representation. In this flawed implementation, the pointer arithmetic used to determine the starting position or offset for the right-channel PCM data incorrectly treats a byte count as if it were an element count of shorts. Since short elements are typically two bytes in size, failing to account for this width multiplier results in an underestimation of the required memory displacement. This miscalculation causes the decoder to write decoded audio samples beyond the boundaries of the allocated heap buffer intended for that specific channel data structure.
From a security operations perspective, this vulnerability falls squarely under CWE-122, which denotes a heap-based buffer overflow where an attacker can overwrite adjacent memory structures due to insufficient bounds checking on dynamically allocated memory regions. The exploitation vector is particularly dangerous because it leverages the Remote Desktop Protocol's sound redirection feature, rdpsnd. A malicious RDP server acting as the audio source can craft and transmit specially constructed MP3 streams that trigger this arithmetic error upon decoding by the client-side FreeRDP instance. This allows for out-of-bounds writes to arbitrary heap memory locations adjacent to the PCM buffer.
The operational impact of successfully exploiting this vulnerability is severe, primarily manifesting as a denial of service through application crash. By corrupting heap metadata or overwriting critical control data structures located near the audio buffer in memory layout, an attacker can cause the FreeRDP client process to terminate unexpectedly. While modern operating systems employ various mitigations such as Address Space Layout Randomization and Data Execution Prevention that may prevent arbitrary code execution from this specific overflow without additional exploitation techniques, the reliability of the crash makes it a potent tool for disrupting remote work environments or potentially serving as an initial foothold in more complex attack chains if combined with other memory corruption primitives.
To mitigate this risk, organizations deploying FreeRDP must ensure they are running version 3.32.0 or later, where the pointer arithmetic logic has been corrected to properly account for element sizes during channel offset calculations. For environments unable to upgrade immediately, disabling LAME support by building with WITH_LAME=OFF is a viable workaround that removes the vulnerable code path entirely, although this may impact audio quality or compatibility depending on system dependencies. Additionally, network-level controls should be implemented to restrict RDP connections only from trusted and verified servers, thereby reducing the attack surface presented by untrusted rdpsnd streams. Regular patch management cycles are essential to address such memory safety issues that stem from low-level C/C++ programming errors in widely used open-source infrastructure components.