CVE-2001-0477 in Webcalendar
Summary
by MITRE
Vulnerability in WebCalendar 0.9.26 allows remote command execution.
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Analysis
by VulDB Data Team • 10/06/2025
The vulnerability identified as CVE-2001-0477 represents a critical remote command execution flaw within WebCalendar version 0.9.26, a widely used web-based calendar application designed for scheduling and event management. This vulnerability stems from insufficient input validation and improper handling of user-supplied data within the application's processing logic, creating an avenue for malicious actors to execute arbitrary commands on the underlying server system. The flaw exists in the application's parameter processing mechanisms where user inputs are directly incorporated into system commands without adequate sanitization or filtering, fundamentally compromising the system's integrity and security posture.
The technical implementation of this vulnerability manifests through improper input validation routines that fail to adequately sanitize or escape user-provided parameters before they are processed by the application. When an attacker crafts malicious input containing command injection sequences, the application's backend processing executes these commands with the privileges of the web server process, typically running with elevated system permissions. This vulnerability directly maps to CWE-77 which describes improper neutralization of special elements used in a command, and CWE-94 which addresses the execution of arbitrary code or commands. The flaw operates at the intersection of command injection and privilege escalation, allowing attackers to gain unauthorized access to system resources and potentially compromise the entire server infrastructure.
The operational impact of this vulnerability extends far beyond simple data compromise, as it enables attackers to execute commands with the privileges of the web server process, potentially leading to complete system compromise. An attacker could leverage this vulnerability to install backdoors, modify system files, access sensitive data, or even establish persistent access to the compromised system. The vulnerability affects organizations using WebCalendar 0.9.26 who may be running on various operating systems including unix-based systems where command execution capabilities are more prevalent. The remote nature of the vulnerability means that attackers do not require physical access to the system, making it particularly dangerous as it can be exploited from anywhere on the internet. This vulnerability aligns with ATT&CK technique T1059 which describes command and scripting interpreter, specifically focusing on the execution of system commands through web applications.
Mitigation strategies for CVE-2001-0477 must address both immediate remediation and long-term security enhancements to prevent similar vulnerabilities from emerging in the future. Organizations should prioritize upgrading to a patched version of WebCalendar as soon as possible, as the vulnerability has been addressed in subsequent releases through proper input validation and sanitization mechanisms. Additionally, implementing proper input filtering and escaping techniques, utilizing parameterized queries where applicable, and employing web application firewalls can provide additional layers of protection. Security hardening measures including restricting web server privileges, implementing proper access controls, and conducting regular security assessments should be implemented. The vulnerability serves as a critical reminder of the importance of input validation and the principle of least privilege in web application security, emphasizing that all user inputs must be treated as potentially malicious and properly sanitized before processing. Organizations should also consider implementing network segmentation and monitoring solutions to detect and prevent exploitation attempts of similar vulnerabilities in their infrastructure.