CVE-2001-0829 in Tomcat
Summary
by MITRE
A cross-site scripting vulnerability in Apache Tomcat 3.2.1 allows a malicious webmaster to embed Javascript in a request for a .JSP file, which causes the Javascript to be inserted into an error message.
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Analysis
by VulDB Data Team • 10/04/2025
The vulnerability identified as CVE-2001-0829 represents a classic cross-site scripting flaw within Apache Tomcat version 3.2.1 that exploits the application server's handling of error messages generated during JSP processing. This weakness arises from insufficient input validation and output encoding mechanisms within the servlet container's error reporting functionality. The vulnerability specifically targets the way Tomcat processes requests for .jsp files and subsequently generates error messages that contain user-supplied data without proper sanitization.
The technical exploitation of this vulnerability occurs when a malicious webmaster crafts a request containing malicious JavaScript code within a .jsp file request. When Tomcat encounters an error during the processing of this malformed request, it incorporates the user-provided JavaScript content directly into the error message that is subsequently returned to the victim's browser. This injection happens because the application server fails to properly escape or filter special characters in the error message generation process, allowing the embedded script to execute in the context of the victim's browser session.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious websites. According to CWE-79, this vulnerability maps directly to Cross-Site Scripting flaws in web applications, where the vulnerability exists due to insufficient sanitization of user-supplied data in web applications. The attack vector leverages the trust relationship between the victim's browser and the vulnerable Tomcat server, potentially allowing an attacker to establish persistent access to user sessions and compromise sensitive information.
From an ATT&CK framework perspective, this vulnerability aligns with T1059.007 for Command and Scripting Interpreter: JavaScript and T1566 for Phishing with Malicious Attachments, as it enables attackers to deliver malicious JavaScript payloads that can execute within legitimate web sessions. The vulnerability demonstrates how insecure input handling in web application servers can create persistent attack surfaces that remain exploitable even when other security measures are in place. The impact is particularly severe in environments where Tomcat serves as a primary web application platform and where multiple users interact with the same server infrastructure.
Mitigation strategies for this vulnerability include immediate patching of the affected Tomcat version to a patched release that implements proper input validation and output encoding mechanisms. Organizations should also implement comprehensive input validation for all user-supplied data, particularly within web application frameworks and servlet containers. The implementation of Content Security Policy headers and proper output encoding in error message generation can provide additional defense-in-depth measures. Regular security assessments of web application servers and continuous monitoring for anomalous request patterns can help detect exploitation attempts. According to OWASP Top 10 2021, this vulnerability category remains relevant in modern web security practices, emphasizing the importance of proper input sanitization and output encoding in preventing XSS attacks across all application layers.