CVE-2026-13527: Critical SQL Injection in SourceCodester Timetabling System

Technical summary

CVE-2026-13527 is a remote SQL injection flaw in SourceCodester Class and Exam Timetabling System 1.0 affecting an unspecified function within /preview4.php. The course_year_section argument fails to properly validate or sanitize user input before incorporating it into SQL queries, enabling attackers to inject arbitrary SQL commands. The vulnerability requires no authentication or user interaction and is accessible over the network. Classification under CWE-74 (Improper Neutralization of Special Elements) and CWE-89 (SQL Injection) reflects inadequate input handling mechanisms. With a CVSS 3.1 score of 7.3 (HIGH), the vulnerability carries moderate impact across confidentiality, integrity, and availability.

Business impact

Educational institutions and organizations operating this timetabling system face direct risk of data breach affecting student records, course schedules, and administrative data. Attackers can exfiltrate sensitive academic information, modify exam schedules to cause operational disruption, or corrupt the database to render the system unreliable. The public availability of exploit code accelerates the timeline to active attacks in the wild, making this an urgent priority for deployment and remediation.

Affected systems

SourceCodester Class and Exam Timetabling System version 1.0 is confirmed vulnerable. Organizations should verify whether they are running this product and immediately determine if they operate version 1.0 or any patched versions released since the vulnerability disclosure on June 29, 2026. Check your application version in administrative interfaces or deployment documentation.

Exploitability

This vulnerability presents high exploitability risk. It requires no authentication, no special configuration, and no user interaction—only network access to the /preview4.php endpoint. The exploit has already been publicly disclosed, meaning attack tools and proof-of-concept code are available to threat actors. Exploitation is straightforward for someone with basic SQL injection knowledge, making this a likely target for opportunistic and targeted attacks.

Remediation

Organizations must apply available security updates from SourceCodester immediately. If no patch exists, implement Web Application Firewall (WAF) rules to block malicious SQL syntax in the course_year_section parameter, enforce input validation on the application side, and consider temporarily restricting network access to /preview4.php if operationally feasible. Database user accounts should follow least-privilege principles to minimize damage from successful injection.

Patch guidance

Contact SourceCodester or visit their official security advisories to obtain and deploy the latest patched version of the Class and Exam Timetabling System. Verify the patch version against the vendor advisory before deployment. Test patches in a staging environment to confirm functionality before production rollout. Establish a maintenance window to minimize disruption to academic calendars.

Detection guidance

Monitor web server logs and WAF logs for suspicious requests to /preview4.php containing SQL keywords (UNION, SELECT, DROP, INSERT, etc.) in the course_year_section parameter. Database audit logs should be reviewed for unexpected queries or data access patterns. Implement intrusion detection signatures targeting SQL injection payloads. Network segmentation and access controls should limit exposure of the application to trusted internal networks where possible.

Why prioritize this

This vulnerability scores HIGH (7.3) due to its complete lack of authentication requirements, network accessibility, and multipart impact on confidentiality, integrity, and availability. The public disclosure of exploits significantly lowers the barrier to attack, and the sensitive nature of academic data makes this a priority target. Institutions should treat this as critical and patch or mitigate within days, not weeks.

Risk score, explained

The CVSS 3.1 score of 7.3 (HIGH) reflects: attack vector NETWORK (AV:N) meaning remote exploitation is trivial; attack complexity LOW (AC:L) indicating no special conditions are required; privileges required NONE (PR:N) and user interaction NONE (UI:N) confirming unauthenticated exploitation; scope UNCHANGED (S:U); and impacts on confidentiality, integrity, and availability all present (C:L/I:L/A:L). The score appropriately captures the severity for an educational institution storing sensitive personal and academic data.

Frequently asked questions