CVE-2026-15558: Online Leave Management System SQLi Flaw

CVE-2026-15558 is a SQL injection vulnerability in CodeAstro Simple Online Leave Management System 1.0 affecting the deletemp.php file. Attackers can remotely exploit this flaw to manipulate databases. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2026-15558 Overview

CVE-2026-15558 is a SQL injection vulnerability in CodeAstro Simple Online Leave Management System 1.0. The flaw resides in the /SimpleOnlineLeave/admin/deletemp.php script, where the ID parameter is passed to a database query without proper sanitization. An authenticated remote attacker can manipulate the ID argument to inject arbitrary SQL statements. The issue is classified under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component). Public disclosure of the exploit technique has occurred through VulDB and a public GitHub issue tracker, increasing the likelihood of opportunistic abuse against exposed installations.

Critical Impact
Authenticated remote attackers can inject SQL statements through the deletemp.php endpoint, potentially exposing or corrupting employee leave records stored in the backend database.

Affected Products

CodeAstro Simple Online Leave Management System 1.0
Vendor: CodeAstro
Vulnerable component: /SimpleOnlineLeave/admin/deletemp.php

Discovery Timeline

2026-07-13 - CVE-2026-15558 published to NVD
2026-07-13 - Last updated in NVD database

Technical Details for CVE-2026-15558

Vulnerability Analysis

The vulnerability exists in the administrative employee deletion workflow of Simple Online Leave Management System 1.0. The deletemp.php script accepts an ID parameter over HTTP and concatenates it directly into a SQL DELETE or SELECT statement executed against the application database. Because the parameter lacks type validation, escaping, or parameterized query binding, an attacker can break out of the intended query context and append arbitrary SQL clauses.

Exploitation requires network access to the admin interface and low-privilege authentication. Successful injection allows attackers to read, modify, or delete records within the accessible database. The vulnerability is tracked under [CWE-74], reflecting the underlying failure to neutralize special SQL metacharacters before passing input to the database driver.

Root Cause

The root cause is direct string concatenation of the user-controlled ID parameter into a SQL query within deletemp.php. The application does not employ prepared statements or input validation routines. This design flaw allows SQL syntax embedded in the request to be interpreted by the MySQL backend as executable query logic.

Attack Vector

An attacker sends a crafted HTTP request to /SimpleOnlineLeave/admin/deletemp.php with a malicious value in the ID parameter. The payload typically contains SQL operators such as UNION SELECT or boolean-based injection patterns to extract data or manipulate query results. The attack is remote, requires low complexity, and only needs low-level authenticated access to the admin panel. Refer to the VulDB CVE-2026-15558 entry and the public GitHub finding for reproduction details.

Detection Methods for CVE-2026-15558

Indicators of Compromise

HTTP requests to /SimpleOnlineLeave/admin/deletemp.php containing SQL metacharacters such as ', --, UNION, or SLEEP( within the ID parameter.
Unusual admin session activity originating from external or unexpected IP addresses.
Database error messages returned to clients, indicating malformed queries triggered by injection attempts.

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the ID query parameter for SQL injection signatures.
Enable verbose PHP and MySQL query logging to correlate anomalous DELETE or SELECT statements against deletemp.php requests.
Review authentication logs for admin accounts issuing repeated requests to the deletion endpoint in short intervals.

Monitoring Recommendations

Alert on any 4xx or 5xx response spikes tied to deletemp.php requests, which often indicate injection probing.
Monitor outbound database connections for unusual query volumes originating from the web application user.
Track admin panel access from geolocations or ASNs outside expected operational baselines.

How to Mitigate CVE-2026-15558

Immediate Actions Required

Restrict access to the /SimpleOnlineLeave/admin/ directory through IP allowlisting or VPN-only reachability.
Rotate credentials for all administrative accounts that could reach the vulnerable endpoint.
Deploy WAF signatures blocking SQL injection payloads targeting the ID parameter of deletemp.php.

Patch Information

As of the last NVD update on 2026-07-13, no official vendor patch has been referenced. Consult the CodeAstro website for vendor updates and refer to the VulDB vulnerability record for tracking remediation status.

Workarounds

Modify deletemp.php to use parameterized queries or prepared statements with bound ID values enforced as integers.
Add server-side input validation ensuring the ID parameter matches a numeric-only regular expression before processing.
Disable the deletion functionality until validated code changes can be tested and deployed in production.

bash

# Example nginx location block restricting admin panel access
location /SimpleOnlineLeave/admin/ {
    allow 10.0.0.0/8;
    deny all;
}