CVE-2025-13575: Fabian Blog Site SQL Injection Flaw

CVE-2025-13575 Overview

CVE-2025-13575 is a SQL injection vulnerability in code-projects Blog Site 1.0, a PHP-based blogging application distributed by Fabian through code-projects.org. The flaw resides in the category_exists function of /resources/functions/blog.php, part of the Category Handler component. Attackers can manipulate the name and field arguments to inject arbitrary SQL into backend database queries. The vulnerability is remotely exploitable, requires low-level authenticated privileges, and affects multiple endpoints that call the vulnerable function. The exploit has been disclosed publicly, increasing the likelihood of opportunistic abuse against exposed instances.

Critical Impact

Remote authenticated attackers can manipulate SQL queries through the name and field parameters in category_exists, leading to unauthorized read or modification of blog database contents.

Affected Products

• code-projects Blog Site 1.0
• Component: Category Handler (/resources/functions/blog.php)
• Vendor: Fabian (distributed via code-projects.org)

Discovery Timeline

• 2025-11-24 - CVE-2025-13575 published to the National Vulnerability Database
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2025-13575

Vulnerability Analysis

The vulnerability is classified under [CWE-89] Improper Neutralization of Special Elements used in an SQL Command and [CWE-74] Improper Neutralization of Special Elements in Output. The category_exists function in /resources/functions/blog.php accepts user-supplied input through the name and field arguments without proper sanitization or parameterized query enforcement. When the function constructs a SQL statement to verify whether a category record exists, attacker-controlled input is concatenated directly into the query string. Multiple application endpoints invoke this function, expanding the exploitable surface across the Blog Site application.

Root Cause

The root cause is the absence of prepared statements or input validation in the category_exists routine. The name and field arguments are passed straight into a dynamically constructed query. Because field likely influences the column reference inside the SQL string, an attacker can break out of expected query semantics and append arbitrary clauses. This pattern is characteristic of legacy PHP applications that rely on string concatenation rather than PDO prepared statements or mysqli parameter binding.

Attack Vector

The attack vector is remote over the network and requires the attacker to hold low-privilege application credentials. An adversary submits crafted values to any endpoint that invokes category_exists, supplying SQL metacharacters in the name or field argument. Successful injection enables data extraction from the underlying database, including user records, blog content, and configuration data. Depending on database privileges, secondary impact can include modifying records or executing stacked queries. Technical proof-of-concept material for this issue is published on the GitHub SQL Injection Guide 1 and GitHub SQL Injection Guide 2 repositories, with vulnerability metadata tracked at VulDB #333339.

Detection Methods for CVE-2025-13575

Indicators of Compromise

• Web server access logs containing SQL metacharacters such as ', ", --, UNION SELECT, or OR 1=1 in requests targeting category-related endpoints of Blog Site 1.0.
• Database error messages or stack traces referencing category_exists or /resources/functions/blog.php returned in HTTP responses.
• Anomalous outbound query patterns from the application database user, particularly INFORMATION_SCHEMA reads.

Detection Strategies

• Inspect HTTP request bodies and query strings for SQL injection payloads sent to endpoints that call category_exists, focusing on the name and field parameters.
• Deploy a web application firewall rule set that flags tautology-based and union-based SQL injection signatures against the Blog Site application path.
• Correlate authentication events with subsequent category-handling requests to identify low-privilege accounts probing the vulnerable function.

Monitoring Recommendations

• Enable verbose query logging on the MySQL or MariaDB backend and alert on queries referencing the categories table with unusual WHERE clauses.
• Monitor the application database account for spikes in query volume, failed statements, or syntax errors.
• Forward web server and database logs to a centralized analytics platform for retroactive hunting once the public proof-of-concept is in active use.

How to Mitigate CVE-2025-13575

Immediate Actions Required

• Restrict network access to Blog Site 1.0 instances by placing them behind authentication gateways or VPNs until a fix is available.
• Audit application accounts and disable or rotate credentials for any low-privilege users that are not strictly required.
• Apply web application firewall rules that block SQL injection payloads targeting the category handler endpoints.

Patch Information

As of the latest NVD update on 2026-04-29, no official vendor patch is referenced for CVE-2025-13575. Administrators should monitor the code-projects resource hub for any forthcoming release of Blog Site that addresses the category_exists function. In the absence of an upstream fix, organizations running the affected version should apply source-level remediation by replacing string concatenation in /resources/functions/blog.php with parameterized queries using PDO or mysqli prepared statements.

Workarounds

• Modify the category_exists function to validate the field argument against an allow-list of known column names before query construction.
• Refactor SQL statements in /resources/functions/blog.php to use prepared statements with bound parameters for the name value.
• Reduce database privileges for the Blog Site application user to read-only on non-essential tables, limiting the impact of successful injection.
• Consider decommissioning the application if it is not business critical, given that code-projects samples are typically educational and not production-hardened.