CVE-2002-0936 in Tomcat
Summary
by MITRE
The Java Server Pages (JSP) engine in Tomcat allows web page owners to cause a denial of service (engine crash) on the web server via a JSP page that calls WPrinterJob().pageSetup(null,null).
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Analysis
by VulDB Data Team • 09/10/2025
The vulnerability identified as CVE-2002-0936 represents a critical denial of service weakness within the Java Server Pages engine of Apache Tomcat web server software. This flaw specifically affects the processing of JSP pages that invoke the WPrinterJob().pageSetup(null,null) method call, which triggers an abnormal termination of the web server engine. The vulnerability stems from inadequate input validation and error handling within the JSP processing pipeline, allowing malicious actors to craft specific JSP content that exploits a fundamental flaw in the printer job handling mechanism. The issue manifests when the JSP engine attempts to process a page containing this particular method invocation without proper safeguards against null parameter inputs.
The technical implementation of this vulnerability leverages the Windows printer job functionality exposed through Java's print API, specifically targeting the WPrinterJob class that interfaces with Windows printing services. When a JSP page containing WPrinterJob().pageSetup(null,null) is executed, the Tomcat JSP engine attempts to process the method call with null parameters, causing an unhandled exception that results in the complete crash of the web server process. This behavior demonstrates a classic lack of proper exception handling and parameter validation within the server-side JSP processing framework. The flaw operates at the application layer and affects the web server's ability to maintain continuous service availability, making it particularly dangerous in production environments where uptime is critical.
The operational impact of CVE-2002-0936 extends beyond simple service disruption to encompass potential business continuity risks and system availability concerns. An attacker exploiting this vulnerability can cause repeated crashes of the Tomcat server, effectively rendering web applications inaccessible to legitimate users and potentially leading to extended downtime. This denial of service condition affects not only the specific JSP pages but can also impact the entire web server instance, as the crash typically results in a complete restart of the server process. The vulnerability is particularly concerning because it requires minimal technical expertise to exploit, as it only requires the creation of a malicious JSP page that can be uploaded or otherwise made accessible to the vulnerable web server. The attack vector demonstrates a weakness in the server's defensive mechanisms and highlights the importance of robust input validation and error handling in web application frameworks.
Mitigation strategies for CVE-2002-0936 should focus on immediate patching of affected Tomcat versions and implementation of proper input validation measures within JSP applications. Organizations should upgrade to patched versions of Apache Tomcat that address the underlying flaw in the JSP engine's handling of printer job methods. Additionally, administrators should implement strict access controls and input validation for JSP pages, particularly those that may interact with system resources or external APIs. The vulnerability aligns with CWE-248, which describes an unchecked exception in the context of Java applications, and represents a classic example of how improper exception handling can lead to system instability. From an ATT&CK framework perspective, this vulnerability corresponds to T1499.004, which covers Server Software Compromise through denial of service attacks. Security configurations should include monitoring for unusual patterns in JSP processing and implementing application-level firewalls to prevent execution of suspicious JSP content. The remediation approach should also include comprehensive testing of JSP applications to identify and eliminate any potential calls to WPrinterJob or similar printer-related APIs that could trigger similar vulnerabilities in the future.