CVE-2026-67288 in FreeRDP
Summary
by MITRE • 08/01/2026
FreeRDP before 3.29.0 contains a null pointer dereference vulnerability in smartcard cache request decoders that accept NULL NDR pointers for LookupName in SCARD_IOCTL_READCACHEA and SCARD_IOCTL_WRITECACHEA operations. When smartcard emulation is enabled, attackers can send crafted smartcard cache requests with NULL lookup-name pointers to trigger strlen() on a null pointer, causing client process termination.
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Analysis
by VulDB Data Team • 08/01/2026
This vulnerability exists within FreeRDP versions prior to 3.29.0 and represents a critical null pointer dereference flaw in the smartcard cache request handling mechanism. The issue specifically affects the SCARD_IOCTL_READCACHEA and SCARD_IOCTL_WRITECACHEA operations where the system processes NDR (Network Data Representation) pointers for LookupName parameters. When smartcard emulation is active, the application fails to properly validate incoming pointer values before attempting to process them, creating an exploitable condition that can be triggered through crafted malicious requests.
The technical implementation of this vulnerability stems from inadequate input validation within the smartcard cache decoders. During normal operation, these functions expect valid NDR pointers containing lookup name data for smartcard operations. However, when attackers supply NULL pointers as the LookupName parameter, the system proceeds to execute strlen() operations on these null references without proper null checks. This fundamental flaw in pointer validation creates an immediate crash condition that terminates the client process, effectively causing a denial of service scenario.
The operational impact of this vulnerability extends beyond simple service disruption as it provides attackers with a reliable method for terminating legitimate FreeRDP client processes. The attack requires minimal prerequisites since it only necessitates establishing a connection to a vulnerable FreeRDP server with smartcard emulation enabled and sending specifically crafted cache requests. This makes the vulnerability particularly dangerous in environments where smartcard authentication is commonly used for secure access control, as attackers can disrupt critical authentication workflows without requiring elevated privileges or complex exploitation techniques.
From a cybersecurity perspective, this vulnerability maps directly to CWE-476 which defines null pointer dereference conditions, and aligns with ATT&CK technique T1059.007 for process injection and command and scripting interpreter usage. The flaw represents a classic example of insufficient input validation in security-critical components, particularly affecting systems that handle sensitive authentication mechanisms through smartcard interfaces. Organizations utilizing FreeRDP for remote desktop connections with smartcard support face significant risk if they have not updated to version 3.29.0 or later.
Mitigation strategies should prioritize immediate deployment of the patched FreeRDP version 3.29.0 or newer, which addresses the null pointer dereference through proper input validation mechanisms. Additionally, network segmentation and access controls should be implemented to limit exposure of vulnerable FreeRDP servers to untrusted networks. System administrators should monitor for suspicious smartcard cache operations and implement logging controls to detect potential exploitation attempts. The vulnerability also underscores the importance of maintaining up-to-date security patches across all remote desktop and authentication infrastructure components.
The root cause analysis reveals that this flaw represents a failure in defensive programming practices within the smartcard subsystem, where proper null pointer checks were omitted during the development phase. This type of vulnerability demonstrates how seemingly minor input validation gaps can create significant security implications in authentication systems. Security teams should conduct comprehensive audits of all smartcard and authentication-related components to identify similar validation weaknesses that could provide attackers with similar denial of service capabilities or potentially more severe exploitation paths.