CVE-2006-0019 in KDE
Summary
by MITRE
Heap-based buffer overflow in the encodeURI and decodeURI functions in the kjs JavaScript interpreter engine in KDE 3.2.0 through 3.5.0 allows remote attackers to execute arbitrary code via a crafted, UTF-8 encoded URI.
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Analysis
by VulDB Data Team • 06/25/2025
The vulnerability identified as CVE-2006-0019 represents a critical heap-based buffer overflow within the kjs JavaScript interpreter engine that was part of the KDE desktop environment. This flaw specifically affects KDE versions 3.2.0 through 3.5.0 and involves the encodeURI and decodeURI functions that are fundamental components of JavaScript URI handling. The vulnerability arises from inadequate bounds checking when processing UTF-8 encoded URIs, creating a condition where maliciously crafted input can exceed the allocated heap memory buffer. This type of vulnerability falls under CWE-121 Heap-based Buffer Overflow, which is classified as a serious memory safety issue that can lead to arbitrary code execution. The attack vector requires remote exploitation through a crafted URI that leverages UTF-8 encoding to trigger the buffer overflow condition.
The technical implementation of this vulnerability occurs when the kjs interpreter processes URI strings that contain specially crafted UTF-8 sequences. The encodeURI and decodeURI functions do not properly validate the length of input strings or the expected output buffer sizes, particularly when handling multi-byte UTF-8 characters. When a malicious URI is processed, the interpreter allocates insufficient heap memory for the resulting encoded or decoded string, allowing subsequent write operations to overflow into adjacent memory regions. This overflow can overwrite critical memory structures including return addresses, function pointers, or other control data, thereby enabling attackers to redirect program execution flow. The vulnerability is particularly dangerous because it can be triggered through web-based interfaces where KDE applications process URIs from external sources, making it a prime candidate for cross-site scripting attacks or web-based exploitation scenarios.
The operational impact of CVE-2006-0019 extends beyond simple code execution to encompass potential system compromise and data breaches. Attackers who successfully exploit this vulnerability can gain complete control over affected KDE applications and potentially the underlying operating system, as the overflow allows for arbitrary code injection. The vulnerability affects desktop environments that rely on KDE's JavaScript interpreter, including various KDE-based applications and web browsers that utilize the kjs engine for JavaScript processing. This presents a significant risk to users who browse the web or open email attachments containing malicious URIs, as the exploitation can occur without user interaction in many scenarios. The vulnerability's classification under the ATT&CK framework would place it within the Execution and Privilege Escalation domains, as successful exploitation leads to arbitrary code execution and potential elevation of privileges.
Mitigation strategies for CVE-2006-0019 focus primarily on updating to patched versions of KDE software, as the vulnerability was addressed in KDE versions 3.5.1 and later. Organizations should implement immediate patch management procedures to upgrade all affected KDE installations and ensure that the JavaScript interpreter engine is updated to a version that properly validates input buffer sizes. Additionally, network administrators can deploy web application firewalls and URI filtering mechanisms to detect and block malicious URIs before they reach vulnerable applications. System hardening measures such as address space layout randomization and stack canaries can provide additional defense-in-depth layers, though these are secondary mitigations since the core issue is in the interpreter's memory management. Security monitoring should include detection of unusual URI processing patterns and potential exploitation attempts targeting the kjs interpreter. The vulnerability serves as a critical reminder of the importance of input validation in scripting engines and highlights the need for regular security updates in desktop environments that incorporate interpreted languages.