CVE-2026-90789: Leave Management System SQL Injection Flaw

CVE-2026-90789 is a SQL injection vulnerability in itsourcecode Leave Management System 1.0 affecting the login.php file. Attackers can exploit the user_email parameter remotely to manipulate database queries. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2026-90789 Overview

CVE-2026-90789 is a SQL injection vulnerability in itsourcecode Leave Management System 1.0. The flaw resides in the /login.php script, where the user_email parameter is passed to a backend SQL query without proper sanitization. Remote attackers can manipulate the parameter to inject arbitrary SQL statements against the underlying database. No authentication is required, and the exploit has been made available to the public. The vulnerability is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component.

Critical Impact
Unauthenticated attackers can inject SQL statements through the login form to read, modify, or exfiltrate data from the Leave Management System database.

Affected Products

itsourcecode Leave Management System 1.0
The vulnerable component is the /login.php endpoint
The vulnerable parameter is user_email

Discovery Timeline

2026-09-14 - CVE CVE-2026-90789 published to NVD
2026-09-14 - Last updated in NVD database

Technical Details for CVE-2026-90789

Vulnerability Analysis

The Leave Management System accepts user-supplied input from the login page and concatenates the user_email value directly into a SQL query executed against the backend database. Because the application does not use prepared statements or apply input sanitization, attackers can break out of the intended string context. This turns an authentication form into a database query interface. Attackers can extract records, enumerate table structures, or bypass authentication depending on the underlying query shape.

The vulnerability is reachable over the network, requires no privileges, and needs no user interaction. Public exploit material is referenced through VulDB entry 403295 and the associated GitHub issue tracker, lowering the barrier for opportunistic exploitation.

Root Cause

The root cause is improper neutralization of special SQL characters in the user_email parameter processed by /login.php. The application composes SQL statements by string concatenation rather than parameterized queries. Any single quote, comment sequence, or SQL keyword supplied by the client is treated as executable syntax by the database engine.

Attack Vector

An unauthenticated attacker sends a crafted HTTP POST request to /login.php with a malicious user_email value. Payloads typically use classic SQL injection primitives such as boolean-based conditions, UNION SELECT clauses, or time-delay functions to confirm and extract data. Because the endpoint is the login form, exploitation can occur before any account is provisioned on the target system.

See the VulDB advisory for CVE-2026-90789 for additional exploitation context.

Detection Methods for CVE-2026-90789

Indicators of Compromise

POST requests to /login.php containing SQL metacharacters such as ', --, /*, UNION, SELECT, or SLEEP( within the user_email field.
Database error messages in web server or PHP logs referencing syntax errors triggered by login attempts.
Unusual outbound database queries returning large result sets shortly after login traffic.
Repeated failed logins from a single source followed by successful authentication without valid credentials.

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the user_email parameter for SQL injection signatures.
Enable database query logging and alert on unusual UNION, INFORMATION_SCHEMA, or timing-function queries originating from the Leave Management System service account.
Correlate HTTP request logs with database error logs to surface injection attempts that produce SQL exceptions.

Monitoring Recommendations

Monitor /login.php for anomalous request rates, oversized parameter values, and non-email content in the user_email field.
Alert on authentication events that do not correspond to a known user record in the application database.
Track egress traffic from the web server for signs of data exfiltration following suspicious login activity.

How to Mitigate CVE-2026-90789

Immediate Actions Required

Restrict network access to the Leave Management System to trusted internal networks or VPN users until a patch is available.
Deploy a WAF rule that blocks SQL metacharacters in the user_email parameter of /login.php.
Review web server and database logs for prior exploitation attempts and rotate any credentials that may have been exposed.
Audit the application database for unauthorized modifications or newly created accounts.

Patch Information

No official vendor patch has been published in the NVD entry at the time of writing. Monitor itsourcecode.com for updated releases, and consult the VulDB submission tracker for remediation updates.

Workarounds

Rewrite the affected query in /login.php to use PHP Data Objects (PDO) or mysqli prepared statements with bound parameters.
Apply server-side input validation that enforces RFC-compliant email syntax on user_email before it reaches any SQL layer.
Run the database account used by the application with the minimum privileges required, denying INFORMATION_SCHEMA and administrative access.
Disable verbose SQL error output in production to reduce information leakage that aids injection tooling.

bash

# Example ModSecurity rule to block SQLi patterns in user_email
SecRule ARGS:user_email "@rx (?i)(union(\s|/\*.*\*/)+select|sleep\s*\(|--\s|';)" \
    "id:1029090789,phase:2,deny,status:403,log,\
     msg:'Possible SQLi against /login.php user_email (CVE-2026-90789)'"