CVE-2026-16227: Class and Exam Timetabling SQLI Flaw

CVE-2026-16227 Overview

CVE-2026-16227 is a SQL injection vulnerability in SourceCodester Class and Exam Timetabling System 1.0. The flaw resides in the /edit_subject.php script, where the ID parameter is passed to a database query without proper sanitization. Attackers can manipulate this parameter to inject arbitrary SQL statements and interact directly with the backend database.

The issue is classified under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component). The exploit has been publicly disclosed, and the attack can be executed remotely over the network without authentication or user interaction.

Critical Impact
Remote, unauthenticated attackers can inject SQL into the ID parameter of /edit_subject.php, potentially exposing or modifying subject records, user data, and other backend content.

Affected Products

SourceCodester Class and Exam Timetabling System 1.0
/edit_subject.php endpoint
Deployments exposing the application to untrusted networks

Discovery Timeline

2026-07-19 - CVE-2026-16227 published to NVD
2026-07-22 - Last updated in NVD database

Technical Details for CVE-2026-16227

Vulnerability Analysis

The vulnerability is a first-order SQL injection reachable through the ID argument of /edit_subject.php. The affected script uses the request parameter directly in a SQL statement, allowing attackers to break out of the intended query context and append additional clauses.

Because the endpoint accepts requests without authentication, any remote client capable of reaching the web server can trigger the injection. The public disclosure means attack tooling can be assembled quickly from the referenced advisories.

Successful exploitation permits read and, depending on the underlying query, write operations against the application database. Exposure includes subject records, related tables, and potentially credentials stored by the timetabling system.

Root Cause

The root cause is the absence of parameterized queries and input validation on the ID parameter in /edit_subject.php. User-supplied data is concatenated into a SQL string, letting adversaries alter query semantics with characters such as ', --, and UNION.

Attack Vector

The attack vector is network-based. An attacker sends a crafted HTTP request that appends malicious SQL through the ID parameter. No credentials are required, and no interaction with legitimate users is needed to trigger the flaw. Refer to the VulDB Vulnerability Report and the GitHub Issue Report for reproduction details.

// Illustrative request pattern (see referenced advisories for details)
GET /edit_subject.php?ID=<injected SQL payload> HTTP/1.1
Host: <target>

Detection Methods for CVE-2026-16227

Indicators of Compromise

HTTP requests to /edit_subject.php containing SQL metacharacters such as ', ", ;, --, or /* in the ID parameter.
Web server or PHP error logs referencing SQL syntax errors triggered by edit_subject.php.
Unusual UNION, SELECT, SLEEP, or BENCHMARK keywords in query strings targeting the timetabling application.

Detection Strategies

Deploy web application firewall (WAF) signatures that flag SQL injection patterns on the ID parameter of /edit_subject.php.
Enable database query logging and alert on anomalous statements originating from the timetabling application service account.
Correlate spikes in 500-level HTTP responses from /edit_subject.php with request payload content.

Monitoring Recommendations

Track outbound data volumes from the database host to detect large result-set exfiltration.
Baseline normal parameter values for ID and alert on non-numeric input.
Retain web access logs long enough to support forensic review after public exploit disclosure.

How to Mitigate CVE-2026-16227

Immediate Actions Required

Restrict network access to the Class and Exam Timetabling System until a fix is available, using firewall rules or a reverse proxy allowlist.
Deploy a WAF rule that rejects non-numeric values or SQL metacharacters submitted to the ID parameter of /edit_subject.php.
Rotate database credentials used by the application if exploitation is suspected.

Patch Information

No official vendor patch is referenced in the CVE record. Administrators should monitor the SourceCodester website and the VulDB CVE-2026-16227 entry for future updates. In the interim, apply source-level fixes to /edit_subject.php by replacing string concatenation with prepared statements and enforcing a strict integer cast on the ID parameter.

Workarounds

Modify /edit_subject.php to validate that ID is an integer before use, for example with intval() or filter_input(INPUT_GET, 'ID', FILTER_VALIDATE_INT).
Refactor the affected query to use PDO or MySQLi prepared statements with bound parameters.
Run the application database under a least-privilege account that cannot modify schema or read unrelated tables.

bash

# Example WAF/nginx rule to reject non-numeric ID values
location = /edit_subject.php {
    if ($arg_ID !~ "^[0-9]+$") {
        return 403;
    }
    include fastcgi_params;
    fastcgi_pass unix:/var/run/php-fpm.sock;
}