CVE-2023-0289 in webcalendar
Summary
by MITRE • 01/13/2023
Cross-site Scripting (XSS) - Stored in GitHub repository craigk5n/webcalendar prior to master.
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Analysis
by VulDB Data Team • 07/07/2025
The vulnerability identified as CVE-2023-0289 represents a stored cross-site scripting flaw within the webcalendar repository maintained by craigk5n on github. This type of vulnerability falls under the broader category of CWE-79 which specifically addresses cross-site scripting attacks where malicious scripts are injected into web applications and subsequently executed in the context of other users' browsers. The stored nature of this vulnerability indicates that the malicious payload is permanently saved within the application's database or storage system, making it persistently dangerous and capable of affecting multiple users over time.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding mechanisms within the webcalendar application. When users submit data through various forms or interfaces within the calendar system, the application fails to properly sanitize or escape potentially malicious content before storing it in the backend database. This allows attackers to inject script code that gets executed whenever other users view the affected content, creating a persistent threat vector that can be exploited across multiple sessions and user interactions.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it can enable attackers to perform a wide range of malicious activities including but not limited to stealing user credentials, modifying calendar entries, accessing sensitive personal information, and potentially escalating privileges within the application. The stored nature of the vulnerability means that even after the initial injection, the malicious code continues to execute whenever users interact with the compromised data, making it particularly dangerous for applications handling personal or business-critical calendar information. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under the T1059.001 category for command and scripting interpreter, as attackers can leverage the XSS vulnerability to execute arbitrary code in the context of other users.
Mitigation strategies for CVE-2023-0289 should focus on implementing comprehensive input validation and output encoding practices throughout the application's codebase. Developers must ensure that all user-supplied data undergoes proper sanitization before being stored or rendered in web pages, with particular attention to HTML encoding of dynamic content. The implementation of Content Security Policy headers can provide additional protection layers, while regular security code reviews and automated vulnerability scanning should be integrated into the development lifecycle. Organizations should also consider implementing proper access controls and monitoring mechanisms to detect potential exploitation attempts, as the vulnerability's persistence makes it particularly valuable for attackers seeking long-term access to calendar systems containing sensitive temporal information. The fix for this vulnerability requires immediate attention from the repository maintainers and users who have deployed the affected software, as the stored nature of the flaw means that any previously injected malicious content remains active until proper remediation is implemented.