CVE-2026-4778: Sales And Inventory System SQLi Vulnerability

CVE-2026-4778 Overview

CVE-2026-4778 is a SQL injection vulnerability in SourceCodester Sales and Inventory System 1.0. The flaw resides in the update_category.php file, where the sid parameter passed through HTTP GET requests is concatenated into a database query without sanitization. Authenticated remote attackers can manipulate this parameter to inject arbitrary SQL statements. A public exploit has been disclosed, increasing the likelihood of opportunistic attacks against exposed installations. The vulnerability is tracked under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command) and CWE-74 (Injection).

Critical Impact

Remote attackers with low-privilege access can extract, modify, or delete data from the application database by injecting SQL through the sid GET parameter.

Affected Products

• SourceCodester Sales and Inventory System 1.0
• Component: update_category.php HTTP GET parameter handler
• Vulnerable parameter: sid

Discovery Timeline

• 2026-03-24 - CVE-2026-4778 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-4778

Vulnerability Analysis

The vulnerability is a classic SQL injection in a PHP web application. The update_category.php endpoint accepts a sid parameter via HTTP GET requests to identify the category record being updated. The application embeds this user-supplied value directly into a SQL statement without using prepared statements or input validation. As a result, the database interprets attacker-controlled input as part of the SQL query syntax.

The attack requires network access to the affected web application and a low-privilege authenticated session. No user interaction is needed beyond submitting a crafted request. According to the disclosed proof-of-concept, the injection point supports standard payload techniques such as UNION-based and boolean-based extraction.

Root Cause

The root cause is improper neutralization of user input before it reaches the SQL interpreter. The sid parameter is concatenated into a query string rather than bound through parameterized queries. The application lacks both server-side validation of expected numeric input and the use of an abstraction layer such as PDO with prepared statements.

Attack Vector

An authenticated attacker sends a crafted HTTP GET request to update_category.php with a malicious sid value. The injected SQL can read arbitrary tables, modify inventory and category data, or perform blind extraction of credentials and session data. Public proof-of-concept material is available in the GitHub SQLi PoC Repository and VulDB entry #352796.

No verified code samples are reproduced here. Refer to the linked references for technical PoC details.

Detection Methods for CVE-2026-4778

Indicators of Compromise

• HTTP GET requests to update_category.php containing SQL keywords such as UNION, SELECT, SLEEP, --, or INFORMATION_SCHEMA in the sid parameter.
• Web server access logs showing abnormally long sid values or URL-encoded SQL syntax.
• Database error messages returned in HTTP responses originating from update_category.php.
• Anomalous read activity against category, user, or credential tables outside normal application workflows.

Detection Strategies

• Deploy web application firewall signatures that match SQL injection patterns on the sid query parameter.
• Enable verbose query logging on the backend database and alert on syntactically unusual statements originating from the application user.
• Correlate authentication events with bursts of GET requests to update_category.php to identify scripted exploitation.

Monitoring Recommendations

• Monitor outbound traffic from the web server for data exfiltration following suspicious requests.
• Track failed and successful login activity for low-privilege accounts that subsequently access category management endpoints.
• Forward web server and database logs to a centralized analytics platform for retention and search.

How to Mitigate CVE-2026-4778

Immediate Actions Required

• Restrict network exposure of the Sales and Inventory System by placing it behind a VPN or IP allowlist until a fix is applied.
• Audit application user accounts and revoke unused low-privilege credentials that could be used to reach the vulnerable endpoint.
• Review web and database logs for prior exploitation indicators referencing update_category.php and the sid parameter.

Patch Information

No official vendor advisory or patch is listed in the public references for SourceCodester Sales and Inventory System 1.0. Operators should monitor the SourceCodester project page for updates and consider applying source-level fixes that replace dynamic SQL with parameterized queries using PDO or MySQLi prepared statements.

Workarounds

• Add server-side input validation to update_category.php that rejects any sid value that is not a positive integer.
• Replace string concatenation in the affected query with prepared statements and bound parameters.
• Deploy a web application firewall rule that blocks requests to update_category.php containing SQL metacharacters in the sid parameter.
• Apply the principle of least privilege to the database account used by the application so injected queries cannot reach sensitive tables.

# Example ModSecurity rule to block SQLi attempts against the sid parameter
SecRule REQUEST_URI "@contains /update_category.php" \
    "chain,phase:2,deny,status:403,id:1004778,msg:'CVE-2026-4778 SQLi attempt on sid parameter'"
    SecRule ARGS:sid "@detectSQLi" "t:none,t:urlDecode"