CVE-2026-13559: Real State Services 1.0 SQLi Vulnerability

CVE-2026-13559 Overview

CVE-2026-13559 is a SQL injection vulnerability in code-projects Real State Services 1.0. The flaw resides in the /single-list_sale.php?action=add endpoint, where the ID argument is passed to a backend database query without adequate sanitization. Attackers can manipulate the ID parameter to inject arbitrary SQL statements, which the application executes against the underlying database. The attack requires no authentication and can be launched remotely over the network. According to the disclosure, exploit details have been publicly released, increasing the likelihood of opportunistic scanning and abuse against exposed instances.

Critical Impact
Unauthenticated remote attackers can inject SQL through the ID parameter of /single-list_sale.php?action=add, potentially reading, modifying, or deleting database records in Real State Services 1.0.

Affected Products

code-projects Real State Services 1.0
Deployments exposing /single-list_sale.php to untrusted networks
Downstream forks or copies of the vulnerable PHP source

Discovery Timeline

2026-06-29 - CVE-2026-13559 published to the National Vulnerability Database (NVD)
2026-06-29 - Last updated in NVD database

Technical Details for CVE-2026-13559

Vulnerability Analysis

The vulnerability is a classic SQL injection classified under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component). The affected script, single-list_sale.php, accepts an ID argument during the add action and concatenates or interpolates that value directly into a SQL statement. Because the input is not validated, escaped, or bound as a parameter, attackers can terminate the intended query and append their own SQL clauses.

Successful exploitation permits interaction with the backend database beyond the developer's intent. Depending on the database user's privileges, attackers may enumerate schema information, extract stored records, alter data, or attempt authentication bypass through injected boolean logic. The disclosure notes the exploit is publicly available, which lowers the technical barrier for attackers scanning for vulnerable Real State Services deployments.

Root Cause

The root cause is missing input validation and the absence of parameterized queries in the request handler for single-list_sale.php?action=add. The ID parameter is treated as trusted data and inserted directly into the SQL statement.

Attack Vector

The attack vector is network-based and unauthenticated. An attacker sends a crafted HTTP request to /single-list_sale.php?action=add with a malicious ID value containing SQL metacharacters. No user interaction is required.

No verified proof-of-concept code is republished here. Refer to the GitHub CVE Issue Tracker and VulDB Vulnerability Details #374567 for technical write-ups of the injection pattern.

Detection Methods for CVE-2026-13559

Indicators of Compromise

HTTP requests to /single-list_sale.php?action=add containing SQL metacharacters such as single quotes, UNION SELECT, --, ;, or OR 1=1 in the ID parameter.
Web server access logs showing repeated ID= values that vary systematically, consistent with automated SQL injection tooling.
Database error messages surfaced in HTTP responses referencing MySQL or MariaDB syntax when parsing the ID value.

Detection Strategies

Deploy web application firewall (WAF) signatures that inspect the ID query parameter on requests to single-list_sale.php for SQL injection payloads.
Correlate web server access logs with database query logs to identify malformed or unusually long queries originating from the add action.
Hunt for outbound data volume anomalies from the web server host that could indicate database exfiltration through blind or union-based injection.

Monitoring Recommendations

Enable verbose query logging on the backend database and alert on syntax errors or queries containing UNION, INFORMATION_SCHEMA, or SLEEP() functions.
Monitor authentication tables and administrative records for unexpected inserts, updates, or deletions.
Alert on repeated 500-series HTTP responses from /single-list_sale.php, which often accompany injection probing.

How to Mitigate CVE-2026-13559

Immediate Actions Required

Restrict network exposure of the Real State Services 1.0 application to trusted networks or place it behind an authenticated reverse proxy until a fix is applied.
Deploy WAF rules to block SQL injection payloads targeting the ID parameter of /single-list_sale.php?action=add.
Audit the database account used by the application and revoke DDL, DROP, and administrative privileges that are not required for normal operation.
Review historical web and database logs for prior exploitation attempts against the vulnerable endpoint.

Patch Information

At the time of publication, no vendor patch is listed in the NVD entry or in the referenced advisories. Consult the Code Projects Resource Hub and the VulDB CVE Reference for CVE-2026-13559 for updated remediation status. If no upstream fix is available, remediation requires modifying the source of single-list_sale.php to use parameterized queries or prepared statements for all database interactions involving the ID argument.

Workarounds

Replace direct string interpolation in single-list_sale.php with PDO or MySQLi prepared statements binding ID as an integer parameter.
Validate that the ID parameter matches a strict numeric pattern (for example, ^[0-9]+$) before it reaches any database logic, rejecting non-conforming requests.
Disable or remove the action=add code path if the functionality is not required in the deployed environment.

bash

# Example nginx rule to block non-numeric ID values on the vulnerable endpoint
location /single-list_sale.php {
    if ($arg_action = "add") {
        if ($arg_id !~ "^[0-9]+$") {
            return 400;
        }
    }
}