CVE-2026-111380 in FreeRDP
Summary
by MITRE • 10/16/2026
FreeRDP from 3.29.0 before 3.32.0 contains an integer overflow in the Apple audin backends (audin_mac.m, audin_ios.m), which compute the audio queue buffer size as FramesPerPacket * 2 * nChannels in UINT32 arithmetic, bypassing the CVE-2026-91962 fix. A malicious RDP server can send FramesPerPacket of 2^30 in the audin Open PDU to wrap the multiplication, causing undersized AudioQueueAllocateBuffer allocations and a heap out-of-bounds write in macOS and iOS clients.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability identified within FreeRDP versions prior to 3.32.0 represents a critical security flaw located specifically within the Apple audio backend implementations for both macOS and iOS platforms. This issue manifests as an integer overflow during the calculation of buffer sizes required for audio processing operations. The specific code paths involved are found in audin_mac.m and audin_ios.m, which handle the initialization and configuration of audio queues on Apple devices. The core technical failure occurs when computing the total size of the audio queue buffers using a formula that multiplies FramesPerPacket by two and then by the number of channels (nChannels). This arithmetic operation is performed using unsigned 32-bit integer types, which imposes a strict upper limit on representable values before wrapping around to zero or small positive numbers.
A malicious Remote Desktop Protocol server can exploit this flaw by sending a specially crafted audin Open PDU that sets the FramesPerPacket parameter to an extremely large value, specifically two raised to the power of thirty. When this value is processed in the unsigned 32-bit arithmetic context, it causes the multiplication result to overflow and wrap around to a significantly smaller number than intended. This underestimation leads directly to undersized memory allocations via AudioQueueAllocateBuffer. Consequently, when audio data is subsequently written into these insufficiently sized buffers during normal playback operations, it results in a heap-based out-of-bounds write vulnerability. This type of memory corruption allows for potential arbitrary code execution or denial of service conditions depending on the specific exploitation context and available mitigations within the operating system.
This vulnerability effectively bypasses previous security fixes, specifically referencing CVE-2026-91962, indicating that earlier remediation efforts did not adequately address this particular arithmetic edge case in the Apple-specific backends. The persistence of such a flaw highlights the complexity of maintaining secure integer handling across multiple platform-specific code paths within large open-source projects like FreeRDP. The impact is severe because it affects client-side applications running on macOS and iOS, which are widely used environments where remote desktop sessions are frequently conducted for professional and personal tasks.
From an industry standards perspective, this vulnerability aligns with CWE-190, which describes integer overflow or wraparound resulting in a weak security decision. The exploitation technique involves manipulating input parameters to cause memory corruption, mapping closely to ATT&CK techniques related to buffer overflows and potentially privilege escalation if the compromised process runs with elevated privileges. Furthermore, it relates to CWE-787, an out-of-bounds write vulnerability that can lead to code execution or system instability.
To mitigate this risk, organizations relying on FreeRDP for remote access must ensure they upgrade immediately to version 3.32.0 or later where the integer overflow has been corrected. Developers should implement rigorous input validation and use safe arithmetic functions that detect overflows before performing calculations involving buffer sizes. Additionally, enabling Address Sanitizer during development and testing phases can help identify similar issues in other parts of the codebase. Security teams should also monitor for any further advisories related to audio processing components in remote desktop clients, as these areas often present complex attack surfaces due to their interaction with low-level system APIs and hardware drivers.