CVE-2026-69795 in Windows
Summary
by MITRE • 10/14/2026
Null pointer dereference in Windows Clipboard Server allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a null pointer dereception within the Microsoft Windows Clipboard Server service, specifically affecting components responsible for handling clipboard data operations. This flaw arises from insufficient validation of input parameters or internal state checks before accessing memory pointers associated with clipboard objects. When an application interacts with the clipboard API and triggers specific sequences that result in malformed or unexpected data structures being passed to the underlying system services, the Clipboard Server may attempt to dereference a pointer that has not been properly initialized or has been set to null due to prior errors or race conditions. In standard programming practices, accessing memory at address zero is prohibited by modern operating systems as it indicates an invalid memory access, typically leading to application crashes. However, in the context of kernel-mode drivers or high-privilege system services like those involved in clipboard management, such a crash can sometimes be exploited if the exception handling mechanism allows for control flow redirection or if the vulnerability occurs during critical initialization phases where state corruption is possible.
From an operational perspective, while null pointer dereferences are often categorized as denial-of-service vulnerabilities due to their tendency to cause service interruptions, this specific instance in Windows presents a more severe risk profile. The ability of an authorized attacker to leverage this flaw for local privilege escalation indicates that the vulnerability allows for arbitrary code execution or memory corruption techniques beyond simple crash induction. This suggests that under certain conditions, such as precise timing attacks or heap spraying techniques combined with the null dereference, an attacker might gain the ability to execute malicious instructions within the security context of the system service. Since clipboard services often run with elevated privileges to ensure seamless interaction between user applications and system-level features, successfully exploiting this vulnerability would grant the attacker a higher level of access than originally intended, potentially allowing them to read sensitive data from other processes, modify system configurations, or install persistent malware.
This type of flaw is commonly associated with CWE-476, which defines null pointer dereference as a software error where a program attempts to use a pointer that references memory not allocated for the object it points to. In many cases, this leads to crashes, but in complex systems like Windows, improper handling can lead to more severe outcomes including information disclosure or privilege escalation depending on how the exception is handled and what state changes occur during the fault. The attack vector aligns with MITRE ATT&CK technique T1059, Command and Scripting Interpreter, particularly when considering the subsequent steps an attacker might take after gaining initial access through this vulnerability to establish persistence or move laterally within a networked environment. It also relates to T1068, Exploitation for Privilege Escalation, as the core impact is increasing user rights from standard user level to system or administrator levels without explicit authentication credentials for those higher privileges.
Mitigation strategies primarily rely on timely application of security patches provided by Microsoft that address the underlying code defects in the Clipboard Server components. Administrators should ensure that all systems are updated with the latest cumulative updates which include fixes for known memory safety issues. Additionally, implementing strict access controls and least privilege principles can limit the impact if an attacker does manage to exploit this vulnerability. Restricting clipboard functionality through group policy or third-party security solutions in high-security environments can reduce the attack surface by preventing unauthorized applications from interacting with system-level clipboard services. Monitoring for unusual process behavior or unexpected service crashes related to clip.exe or associated DLLs can also aid in early detection of exploitation attempts, allowing incident response teams to investigate and contain potential breaches before significant damage occurs.