CVE-1999-0392 in cgic Library
Summary
by MITRE
Buffer overflow in Thomas Boutell's cgic library version up to 1.05.
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability identified as CVE-1999-0392 represents a critical buffer overflow flaw within Thomas Boutell's cgic library version 1.05 and earlier. This library serves as a common gateway interface implementation for processing web forms and handling HTTP requests in server-side web applications. The buffer overflow occurs during the processing of input data, specifically when handling form submissions or query parameters that exceed predetermined memory boundaries. The flaw stems from inadequate bounds checking mechanisms within the library's input parsing routines, allowing malicious actors to overwrite adjacent memory locations through carefully crafted input sequences.
The technical implementation of this vulnerability involves the cgic library's failure to properly validate the length of incoming data before copying it into fixed-size buffers. When a user submits a form with excessively long input fields, the library attempts to store this data in memory segments without sufficient boundary verification. This oversight creates an exploitable condition where an attacker can craft input data that overflows the allocated buffer space, potentially corrupting adjacent memory regions including stack variables, return addresses, or other critical program data structures. The vulnerability falls under the CWE-121 category of stack-based buffer overflow, which represents one of the most prevalent and dangerous classes of memory corruption vulnerabilities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides potential attackers with opportunities for arbitrary code execution within the web server process context. When exploited successfully, the buffer overflow can allow remote attackers to overwrite the instruction pointer or other critical memory locations, enabling them to redirect program execution flow and potentially execute malicious code with the privileges of the web server process. This presents significant security implications for web applications relying on the affected cgic library, as it could lead to complete system compromise, data exfiltration, or persistent backdoor installation. The vulnerability affects any web application deployed on systems using cgic library versions prior to 1.06, making it particularly concerning for legacy web server environments.
Mitigation strategies for CVE-1999-0392 primarily focus on immediate library updates and input validation enhancements. System administrators should upgrade to cgic library version 1.06 or later, which includes proper bounds checking and memory management improvements to prevent the overflow conditions. Additionally, implementing robust input validation at multiple layers of the application stack provides defense-in-depth protection, ensuring that even if the library vulnerability remains unpatched, malicious input data is rejected before it can cause harm. Network-level protections such as web application firewalls and intrusion detection systems can monitor for suspicious input patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of following secure coding practices, particularly in legacy software systems, and demonstrates how seemingly minor implementation flaws can create significant security risks. Organizations should conduct comprehensive vulnerability assessments of their web application infrastructure to identify all systems utilizing vulnerable versions of the cgic library and ensure timely remediation through proper patch management procedures.