CVE-2023-6816

Se encontró un fallo en el servidor X.Org. Tanto DeviceFocusEvent como la respuesta de XIQueryPointer contienen un bit para cada botón lógico actualmente presionado. Los botones se pueden asignar arbitrariamente a cualquier valor hasta 255, pero el servidor X.Org solo asignaba espacio para la cantidad particular de botones del dispositivo, lo que provocaba un desbordamiento de búfer en la región Heap de la memoria si se usaba un valor mayor.

This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the handling of SetInputFocus requests. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated array. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root.

USN-6587-1 fixed vulnerabilities in X.Org X Server. The fix was incomplete resulting in a possible regression. This update fixes the problem. Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled memory when processing the DeviceFocusEvent and ProcXIQueryPointer APIs. An attacker could possibly use this issue to cause the X Server to crash, obtain sensitive information, or execute arbitrary code. Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled reattaching to a different master device. An attacker could use this issue to cause the X Server to crash, leading to a denial of service, or possibly execute arbitrary code. Olivier Fourdan and Donn Seeley discovered that the X.Org X Server incorrectly labeled GLX PBuffers when used with SELinux. An attacker could use this issue to cause the X Server to crash, leading to a denial of service. Olivier Fourdan discovered that the X.Org X Server incorrectly handled the curser code when used with SELinux. An attacker could use this issue to cause the X Server to crash, leading to a denial of service. Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled memory when processing the XISendDeviceHierarchyEvent API. An attacker could possibly use this issue to cause the X Server to crash, or execute arbitrary code. Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled devices being disabled. An attacker could possibly use this issue to cause the X Server to crash, or execute arbitrary code.