CVE-2026-40816: mb24alarm.php SQLi Vulnerability

CVE-2026-40816 Overview

CVE-2026-40816 is an unauthenticated SQL injection vulnerability in the mb24alarm.php file's _mb24confi_getTagAlarm function. The flaw stems from improper neutralization of special elements used in a SQL SELECT statement [CWE-89]. Remote attackers can exploit the issue over the network without authentication or user interaction. Successful exploitation results in a total loss of confidentiality of data accessible to the backend database. The vulnerability is tracked under CERT-VDE Security Advisory VDE-2026-044.

Critical Impact
An unauthenticated network attacker can read arbitrary database contents by injecting crafted input into the _mb24confi_getTagAlarm function.

Affected Products

Product containing the mb24alarm.php component (see CERT-VDE advisory VDE-2026-044)
Specific affected vendor and version data not enumerated in NVD at publication
Refer to the CERT-VDE advisory for the authoritative affected product list

Discovery Timeline

2026-05-27 - CVE-2026-40816 published to NVD
2026-05-27 - Last updated in NVD database

Technical Details for CVE-2026-40816

Vulnerability Analysis

The vulnerability resides in the _mb24confi_getTagAlarm function within mb24alarm.php. The function constructs a SQL SELECT query using attacker-controllable input without neutralizing SQL metacharacters. An unauthenticated remote attacker can submit crafted HTTP request parameters to alter the structure of the query.

Because the injection occurs in a SELECT statement, attackers can append UNION SELECT clauses or boolean and time-based payloads. This allows extraction of arbitrary rows and columns from any database accessible to the application's database account. The impact is classified as a total loss of confidentiality, while integrity and availability remain unaffected per the CVSS vector.

Root Cause

The root cause is improper neutralization of special elements used in a SQL command [CWE-89]. The _mb24confi_getTagAlarm function concatenates untrusted input into a SQL SELECT query instead of using parameterized queries or prepared statements. No input validation, escaping, or allowlist filtering is applied before the query reaches the database engine.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker sends an HTTP request to the endpoint that invokes _mb24confi_getTagAlarm in mb24alarm.php with a malicious payload in the vulnerable parameter. The backend database parses the injected SQL fragment and returns data the attacker would not otherwise be able to access.

No verified public proof-of-concept exploit code is available at the time of writing. Refer to the CERT-VDE Security Advisory for vendor-supplied technical detail.

Detection Methods for CVE-2026-40816

Indicators of Compromise

HTTP requests targeting mb24alarm.php containing SQL metacharacters such as ', ", --, ;, UNION, or SELECT in query parameters
Unexpected outbound database query patterns referencing system tables such as information_schema.tables or information_schema.columns
Web server access logs showing high-entropy or encoded payloads sent to mb24alarm.php from a single source
Database error messages logged after requests to mb24alarm.php, indicating malformed query attempts

Detection Strategies

Deploy web application firewall (WAF) signatures that match SQL injection patterns against the mb24alarm.php URI
Enable database query logging and alert on SELECT statements containing union-based or boolean-based injection markers
Review application logs for repeated requests to the _mb24confi_getTagAlarm endpoint from unauthenticated sessions

Monitoring Recommendations

Forward web server, application, and database logs to a centralized SIEM for correlation
Alert on anomalous response sizes from mb24alarm.php that may indicate successful data exfiltration
Monitor for sequential requests demonstrating reconnaissance of database schema, such as iteration through column or table names

How to Mitigate CVE-2026-40816

Immediate Actions Required

Apply the vendor patch referenced in CERT-VDE Security Advisory VDE-2026-044 as soon as it is available
Restrict network access to the affected application using firewall rules or VPN-only access until patching is complete
Audit web server and database logs for evidence of prior exploitation against mb24alarm.php

Patch Information

Consult the CERT-VDE Security Advisory for vendor patch availability and fixed version information. The advisory is the authoritative source for remediation details associated with CVE-2026-40816.

Workarounds

Block external access to mb24alarm.php at the reverse proxy or WAF if the endpoint is not required for normal operation
Deploy WAF rules that reject requests to mb24alarm.php containing SQL keywords or metacharacters in parameter values
Enforce least-privilege on the database account used by the application to limit data accessible through injection

bash

# Example NGINX configuration to block external access to the vulnerable endpoint
location = /mb24alarm.php {
    allow 10.0.0.0/8;     # internal management network only
    deny all;
    return 403;
}