CVE-2026-103543: Leave Management System SQL Injection

CVE-2026-103543 Overview

CVE-2026-103543 is a SQL injection vulnerability in itsourcecode Leave Management System 1.0. The flaw resides in the /module/leavetype/controller.php file, where manipulation of the LEAVTID parameter allows attackers to inject arbitrary SQL statements. The vulnerability is classified under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component).

The issue is remotely exploitable and requires only low privileges. The exploit details have been publicly disclosed, increasing the probability of opportunistic abuse against exposed deployments. Successful exploitation can lead to unauthorized database access, data tampering, and limited availability impact against the application's backend.

Critical Impact
Authenticated remote attackers can inject SQL statements through the LEAVTID parameter to read, modify, or disrupt data stored in the Leave Management System database.

Affected Products

itsourcecode Leave Management System 1.0
Vulnerable file: /module/leavetype/controller.php
Affected parameter: LEAVTID

Discovery Timeline

2026-10-01 - CVE-2026-103543 published to NVD
2026-10-01 - Last updated in NVD database

Technical Details for CVE-2026-103543

Vulnerability Analysis

The vulnerability exists in the leave type controller component of itsourcecode Leave Management System 1.0. The application accepts the LEAVTID request parameter and incorporates it into a SQL statement without proper sanitization or parameterization. Attackers can supply crafted input that alters the structure of the resulting query.

Because the attack is launched over the network and requires only low privileges, any authenticated user of the application can trigger the flaw. Exploitation does not require user interaction. The disclosed proof-of-concept lowers the barrier for opportunistic exploitation of exposed instances.

Root Cause

The root cause is improper neutralization of special elements in a downstream SQL query, consistent with [CWE-74]. The controller.php script concatenates the LEAVTID value directly into a database query instead of using prepared statements with bound parameters. Any input containing SQL metacharacters is interpreted as part of the query logic.

Attack Vector

An authenticated attacker sends an HTTP request to the vulnerable endpoint handling leave type operations and supplies a malicious LEAVTID value. The injected payload modifies the SQL query to extract data from arbitrary tables, bypass authorization logic, or alter stored records. Public disclosure of the exploit means attackers can readily adapt existing payloads to target production deployments.

For technical specifics, refer to the VulDB CVE-2026-103543 Details and the GitHub Issue #17 Discussion.

Detection Methods for CVE-2026-103543

Indicators of Compromise

Unusual HTTP requests to /module/leavetype/controller.php containing SQL metacharacters such as single quotes, UNION, SELECT, SLEEP, or comment sequences in the LEAVTID parameter.
Database error messages or stack traces returned to clients that reference the leave type query path.
Spikes in query execution time or anomalous row counts returned from the leave type tables.

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the LEAVTID parameter for SQL injection patterns and block requests matching known payload signatures.
Enable verbose database query logging and correlate requests to /module/leavetype/controller.php with queries containing tautologies (for example, OR 1=1) or stacked statements.
Review application access logs for repeated requests from a single source iterating through payload variations against the leave type endpoint.

Monitoring Recommendations

Alert on authentication events followed by SQL error responses from the Leave Management System host.
Monitor outbound database traffic for unusual data volumes that could indicate exfiltration via injection.
Track changes to leave type records and administrative tables to catch unauthorized modifications early.

How to Mitigate CVE-2026-103543

Immediate Actions Required

Restrict network access to the Leave Management System application to trusted users only, using VPN or IP allow-listing where feasible.
Rotate credentials for any application database accounts and audit recent database activity on the affected system.
Disable or remove the /module/leavetype/controller.php endpoint if the leave type functionality is not required.

Patch Information

No vendor patch is referenced in the available advisories at the time of publication. Administrators should monitor the IT Source Code Overview and the VulDB Vulnerability #412353 Details page for updated remediation guidance. In the absence of an official fix, source-level remediation should refactor the LEAVTID query to use parameterized prepared statements.

Workarounds

Implement a WAF rule set that blocks SQL injection payloads in the LEAVTID parameter.
Enforce strict server-side input validation that accepts only numeric values for LEAVTID and rejects all other input.
Apply least-privilege permissions to the database account used by the application so that injection cannot access unrelated tables.
Audit all other controller files in the application for similar unsafe query construction patterns.

bash

# Example WAF rule concept (ModSecurity-style) to block SQLi in LEAVTID
SecRule ARGS:LEAVTID "@rx (?i)(union(\s)+select|or\s+1=1|--|;|/\*|sleep\(|benchmark\()" \
  "id:1026103543,phase:2,deny,status:403,msg:'Potential SQLi against LEAVTID (CVE-2026-103543)'"