CVE-2026-111375 in FreeRDP
Summary
by MITRE • 10/16/2026
FreeRDP from 3.0.0 before 3.32.0 contains an out-of-bounds read vulnerability in the Windows RAIL client that allows malicious RDP servers to trigger heap over-reads by sending non-NUL-terminated window titles. Attackers can send a full-length WINDOW_ORDER_FIELD_TITLE update that wf_rail_window_common passes to SetWindowTextW, corrupting titles or crashing the client.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability identified in FreeRDP versions prior to 3.32.0 represents a critical security flaw within the Windows Remote Application List (RAIL) client implementation. This component is responsible for rendering remote desktop applications as native windows on the local host, providing an integrated user experience that mimics locally installed software. The specific defect lies in how the application handles window title data received from the RDP server during session updates. When a malicious or compromised RDP server sends WINDOW_ORDER_FIELD_TITLE update packets containing non-NUL-terminated strings, the FreeRDP client fails to validate string boundaries before processing them for display purposes. This lack of rigorous input validation allows an attacker who controls the remote desktop environment to exploit this weakness by crafting specific network payloads that exceed expected buffer limits or omit necessary termination characters.
From a technical perspective, the root cause is classified as CWE-126, which denotes Buffer Over-read. The vulnerability manifests when the function wf_rail_window_common processes incoming title data and passes it directly to Windows API functions such as SetWindowTextW without ensuring null-termination or length verification. Because C-style strings rely on a terminating NUL character to define their end, receiving input that lacks this delimiter causes the application to read memory beyond the allocated buffer boundary. This out-of-bounds read can lead to several adverse outcomes depending on the specific state of the heap and the data encountered during the excessive read operation. The immediate operational impact includes potential corruption of window title fields within the client interface, which disrupts normal user interaction with remote applications. More severely, if the memory accessed contains sensitive information or triggers an exception due to invalid address access, it can result in a denial-of-service condition by crashing the FreeRDP client process entirely.
This vulnerability aligns with ATT&CK technique T1059, specifically Command and Scripting Interpreter sub-techniques related to system command execution via GUI interactions, although its primary immediate effect is stability degradation rather than direct code execution. However, heap over-read vulnerabilities are frequently precursors to more severe exploits such as information disclosure or arbitrary code execution if the attacker can control subsequent memory writes based on leaked data. The ability of an untrusted remote server to trigger these conditions highlights a significant trust boundary violation where client-side assumptions about input integrity are exploited. Organizations relying on FreeRDP for accessing sensitive infrastructure must recognize that even display-layer vulnerabilities in RAIL mode pose substantial risks due to the privileged nature often associated with desktop environments and potential lateral movement opportunities if combined with other flaws.
Mitigation strategies primarily involve upgrading to version 3.32.0 or later of FreeRDP, where developers have implemented proper bounds checking and string termination validation within the wf_rail_window_common function. Until an upgrade is feasible, administrators should restrict access to RAIL-enabled sessions by enforcing strict network segmentation policies that prevent untrusted networks from initiating connections to vulnerable clients. Additionally, deploying intrusion detection systems capable of identifying anomalous RDP packet structures may provide a layer of defense against exploitation attempts. Security teams are advised to audit their remote desktop infrastructure for any remaining instances of older FreeRDP builds and ensure that all client endpoints receive timely patches addressing this specific heap over-read condition to maintain the confidentiality and availability of remote computing resources.