CVE-2026-16202 in Class and Exam Timetabling System
Summary
by MITRE • 07/19/2026
A vulnerability was determined in SourceCodester Class and Exam Timetabling System 1.0. Affected by this vulnerability is an unknown functionality of the file /CYS.php. This manipulation of the argument course causes cross site scripting. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized.
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Analysis
by VulDB Data Team • 07/19/2026
The vulnerability identified in SourceCodester Class and Exam Timetabling System 1.0 represents a critical cross site scripting weakness that undermines the application's security posture. This flaw exists within the /CYS.php file where user input is improperly handled, creating an avenue for malicious actors to inject arbitrary JavaScript code into the application's response. The vulnerability specifically manifests when the course parameter is manipulated, allowing attackers to execute scripts in the context of other users' browsers who interact with the affected system.
This cross site scripting vulnerability operates under CWE-79 which categorizes it as a failure to sanitize input data before rendering it in web responses. The attack vector is remote, meaning that malicious actors can exploit this weakness without requiring physical access to the target system or network. The publicly disclosed nature of the exploit significantly increases the risk surface, as threat actors can readily utilize existing code to compromise vulnerable installations. The vulnerability's impact extends beyond simple data theft, as it enables session hijacking, credential theft, and potential lateral movement within compromised networks where the application is deployed.
The operational consequences of this vulnerability are severe for organizations utilizing this timetabling system, particularly in educational environments where sensitive academic data and personal information may be exposed. Attackers can leverage this weakness to manipulate timetable displays, inject malicious content into user sessions, or redirect victims to phishing sites designed to capture credentials. The remote exploit capability means that adversaries can target systems from anywhere on the internet, making the attack surface extremely broad and difficult to monitor effectively. This vulnerability directly aligns with ATT&CK technique T1566 which encompasses social engineering tactics including spearphishing with attachments or links, where XSS serves as a foundational primitive for more sophisticated attacks.
Organizations should immediately implement comprehensive mitigation strategies including input validation and output encoding for all parameters passed to the /CYS.php endpoint. The recommended approach involves implementing strict parameter validation that filters out potentially malicious input patterns and employs proper HTML entity encoding when rendering user-supplied data in web responses. Additionally, implementing a robust content security policy can provide additional layers of protection against script execution. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities across the entire application codebase, as this weakness may indicate broader input handling issues that require systematic remediation rather than isolated fixes.