CVE-2000-0285 in X11r6
Summary
by MITRE
Buffer overflow in XFree86 3.3.x allows local users to execute arbitrary commands via a long -xkbmap parameter.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 04/21/2026
The vulnerability described in CVE-2000-0285 represents a critical buffer overflow flaw within the XFree86 3.3.x graphics subsystem that affects the X Window System implementation. This issue specifically manifests when processing command-line parameters, particularly the -xkbmap option, which is used to specify keyboard mapping files for X11 applications. The flaw exists in the way the software handles user-supplied input parameters, creating a condition where maliciously crafted input can overwrite adjacent memory locations beyond the intended buffer boundaries. Such buffer overflow conditions are particularly dangerous because they can be exploited to execute arbitrary code with the privileges of the affected process, typically the X server itself.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw occurs in the command-line argument parsing logic where the -xkbmap parameter is processed without adequate input validation or length restriction checks. When a local user provides an excessively long argument value, the program fails to properly terminate the buffer or validate the input length, resulting in memory corruption that can be leveraged for exploitation. This type of vulnerability is classified as a local privilege escalation vector since it requires local system access but can potentially elevate privileges to the level of the X server process, which often runs with elevated permissions.
The operational impact of CVE-2000-0285 extends beyond simple denial of service scenarios, as it creates a pathway for attackers to gain unauthorized system access and execute malicious code. In a typical X11 environment, the X server runs with significant privileges to manage graphics hardware and user interfaces, making successful exploitation particularly dangerous. Attackers could potentially use this vulnerability to install backdoors, modify system files, or establish persistent access to the compromised system. The local nature of the attack means that an attacker must already have access to the system, but once exploited, the vulnerability provides a means to escalate privileges and maintain access. This vulnerability affects all systems running XFree86 3.3.x versions, including various unix and linux distributions that relied on this graphics subsystem for their desktop environments.
Mitigation strategies for CVE-2000-0285 primarily focus on immediate software updates and system hardening measures. The most effective approach involves upgrading to a patched version of XFree86 that addresses the buffer overflow condition through proper input validation and bounds checking. System administrators should also implement input sanitization measures that limit the maximum length of command-line parameters and employ runtime protections such as stack canaries or address space layout randomization to make exploitation more difficult. Additionally, implementing least privilege principles by running X server processes with minimal required permissions can reduce the potential impact of successful exploitation. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which covers local privilege escalation through software exploitation, making it a critical target for security hardening and monitoring efforts.