CVE-2025-40731: Daily Expense Manager SQLi Vulnerability

CVE-2025-40731 Overview

CVE-2025-40731 is a SQL injection vulnerability [CWE-89] in Code-projects Daily Expense Manager v1.0. The flaw resides in the /update.php endpoint, where the pname, pprice, and id parameters are passed to backend SQL queries without proper sanitization. Authenticated attackers can inject arbitrary SQL statements to read, create, modify, or delete database contents. The vulnerability carries a CVSS 4.0 score of 8.7 and affects the confidentiality, integrity, and availability of the underlying database.

Critical Impact
Attackers with low-privilege access can fully compromise the application database through the /update.php parameters, enabling data theft, record tampering, and destructive operations against expense data.

Affected Products

Code-projects Daily Expense Manager 1.0
Deployments using the vulnerable /update.php handler
Web applications built on the unpatched code-projects codebase

Discovery Timeline

2025-06-30 - CVE-2025-40731 published to NVD
2025-07-07 - Last updated in NVD database

Technical Details for CVE-2025-40731

Vulnerability Analysis

The vulnerability is a classic SQL injection issue in the update workflow of Daily Expense Manager v1.0. The /update.php script accepts user-controlled values for pname (product name), pprice (product price), and id (record identifier). These inputs are concatenated directly into SQL statements executed against the application's database. Because the application does not use parameterized queries or input validation, attackers can break out of the intended SQL context and append arbitrary statements.

Successful exploitation allows attackers to execute SELECT, INSERT, UPDATE, and DELETE operations against any table the database user can access. According to the Incibe Security Notice, the flaw is one of several issues affecting this application.

Root Cause

The root cause is improper neutralization of special elements used in an SQL command [CWE-89]. The /update.php handler builds SQL queries through string concatenation using HTTP request parameters. No prepared statements, stored procedures, or input filtering are applied before the query reaches the database engine.

Attack Vector

The attack vector is network-based and requires low privileges. An authenticated user submits crafted values in the pname, pprice, or id parameters to /update.php. The injected SQL payload alters the query logic, enabling data exfiltration through UNION clauses, record tampering through stacked queries, or destructive operations such as DROP TABLE. No user interaction is required beyond submitting the malicious request.

No verified exploit code is publicly documented for this CVE. See the Incibe Security Notice for additional technical context.

Detection Methods for CVE-2025-40731

Indicators of Compromise

HTTP POST or GET requests to /update.php containing SQL metacharacters such as ', --, ;, or UNION SELECT in the pname, pprice, or id parameters.
Unexpected database errors or 500 responses tied to /update.php in web server logs.
Anomalous database write activity, including unexpected INSERT, UPDATE, or DELETE operations against expense tables.
New or modified database records that do not correspond to legitimate user activity.

Detection Strategies

Inspect web application firewall (WAF) logs for SQL injection signatures targeting the /update.php endpoint.
Enable database query logging and alert on queries containing tautologies (OR 1=1) or stacked statements originating from the application service account.
Correlate authentication events with bulk database modifications to identify abuse from compromised low-privilege accounts.

Monitoring Recommendations

Monitor outbound traffic from the database host for unusual volumes that may indicate data exfiltration.
Track schema changes and privileged SQL statements against the Daily Expense Manager database in real time.
Forward web and database logs into a centralized SIEM for correlation and retention.

How to Mitigate CVE-2025-40731

Immediate Actions Required

Restrict network access to the Daily Expense Manager application until a fix is applied.
Place the /update.php endpoint behind a WAF with SQL injection rules tuned for the pname, pprice, and id parameters.
Audit the application database for unauthorized records, modified entries, or dropped tables.
Rotate database credentials and review account privileges granted to the application service user.

Patch Information

No vendor patch is referenced in the NVD entry at the time of publication. Review the Incibe Security Notice for vendor updates and replace string-concatenated SQL with parameterized queries in /update.php if maintaining a forked copy of the codebase.

Workarounds

Apply input validation that rejects non-numeric values in the id and pprice parameters before they reach SQL queries.
Refactor /update.php to use prepared statements with bound parameters via PDO or MySQLi.
Enforce least privilege on the database account used by the application, removing DROP and schema-modification rights.
Disable or remove the Daily Expense Manager deployment if it is not business-critical.

bash

# Configuration example: deny SQL metacharacters at the WAF layer (ModSecurity)
SecRule ARGS:pname|ARGS:pprice|ARGS:id "@rx (?i)(union(.*?)select|--|;|/\*|or\s+1=1)" \
    "id:1040731,phase:2,deny,status:403,msg:'CVE-2025-40731 SQLi attempt on /update.php'"