CVE-2026-57156 in FreeRDP
Summary
by MITRE • 07/10/2026
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0 on 32-bit builds, FreeRDP clients contain an integer overflow in update_read_delta_points in libfreerdp/core/orders.c when multiplying an attacker-controlled point count by sizeof(DELTA_POINT), allowing a malicious RDP peer to allocate an undersized heap buffer and then write beyond it during initialization. This issue is fixed in version 3.28.0.
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Analysis
by VulDB Data Team • 07/10/2026
The vulnerability under discussion affects FreeRDP implementations prior to version 3.28.0, specifically impacting 32-bit builds of the remote desktop protocol client. This integer overflow occurs within the update_read_delta_points function located in libfreerdp/core/orders.c, representing a critical flaw that enables remote code execution through memory corruption. The issue stems from a multiplication operation between an attacker-controlled point count and the size of DELTA_POINT structure, which can result in wraparound behavior due to 32-bit integer limitations. When this multiplication produces an unexpectedly small value, it leads to allocation of insufficient heap buffer space that cannot accommodate the actual data being written.
The technical exploitation of this vulnerability follows a predictable pattern where a malicious RDP peer controls the point count parameter during protocol initialization. This allows the attacker to manipulate the buffer allocation size calculation, resulting in a heap-based buffer overflow condition. The flaw specifically relates to CWE-190, which covers integer overflow and wraparound conditions, making it particularly dangerous as it can be triggered through normal network communication without requiring authentication or specialized privileges. The vulnerability represents a classic case of improper input validation where the system fails to properly verify that multiplication operations will not exceed maximum integer limits.
From an operational standpoint, this vulnerability creates significant risk for organizations relying on FreeRDP clients for remote desktop connectivity. Attackers can leverage this flaw to execute arbitrary code on vulnerable systems, potentially leading to complete compromise of endpoints and network access. The impact extends beyond individual client machines as successful exploitation could enable lateral movement within networks where RDP services are deployed. This vulnerability particularly affects environments where 32-bit FreeRDP implementations are used for remote access or desktop virtualization solutions, making it a high-priority concern for system administrators managing these components.
Mitigation strategies should prioritize immediate deployment of FreeRDP version 3.28.0 or later, which contains the necessary patches to address the integer overflow condition. Organizations should also implement network segmentation and access controls to limit RDP service exposure, while monitoring for suspicious connection patterns that might indicate exploitation attempts. The fix typically involves proper bounds checking of multiplication operations and ensuring that buffer allocations are validated against maximum possible values before memory allocation occurs. Security teams should consider implementing intrusion detection systems capable of identifying anomalous RDP traffic patterns and conduct regular vulnerability assessments to ensure all FreeRDP implementations remain updated against known security flaws. This vulnerability also highlights the importance of proper integer handling in network protocol implementations, particularly when dealing with attacker-controllable data inputs that could lead to memory corruption conditions.