CVE-1999-1107 in KDE
Summary
by MITRE
Buffer overflow in kppp in KDE allows local users to gain root access via a long PATH environmental variable.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-1107 represents a critical buffer overflow flaw within the kppp component of the KDE desktop environment, a widely used graphical user interface for unix-like operating systems. This issue specifically affects the handling of environmental variables during the execution of network connection scripts, creating a pathway for local privilege escalation attacks. The vulnerability manifests when a malicious user manipulates the PATH environment variable to exceed the allocated buffer space, enabling arbitrary code execution with elevated privileges.
The technical root cause of this vulnerability stems from improper input validation and memory management within the kppp utility, which is responsible for managing PPP (Point-to-Point Protocol) connections in KDE environments. When the system processes network connection scripts, it fails to properly bounds-check the PATH environmental variable, allowing attackers to overwrite adjacent memory locations. This classic buffer overflow condition occurs because the application uses unsafe string handling functions that do not validate the length of input data against the allocated buffer size. The flaw falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking enables memory corruption that can be exploited to execute arbitrary code.
The operational impact of this vulnerability is severe as it provides local users with the ability to escalate their privileges to root level without requiring authentication or physical access to the system. Attackers can leverage this weakness by crafting a specially constructed PATH variable that, when processed by kppp, triggers the buffer overflow and subsequently executes malicious code with elevated privileges. This type of local privilege escalation vulnerability is particularly dangerous in multi-user environments where users may have legitimate access to the system but should not possess administrative capabilities. The attack vector is relatively simple to execute since it only requires local system access and knowledge of the vulnerable application's behavior.
Mitigation strategies for CVE-1999-1107 should focus on immediate patching of the affected KDE components, particularly the kppp utility and related PPP connection handling modules. System administrators should implement strict environmental variable validation and bounds checking mechanisms to prevent malicious input from causing buffer overflows. The vulnerability aligns with ATT&CK technique T1068 which describes the exploitation of vulnerabilities to gain privileges, and T1059 which covers the execution of commands through various interfaces. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and non-executable stack protections to make exploitation more difficult. Additionally, regular security audits of system components and environmental variable handling should be conducted to identify similar vulnerabilities that may exist in other applications within the KDE ecosystem or related network management tools.