CVE-2026-40818: _mb24confi_getDevice SQLi Vulnerability

CVE-2026-40818 Overview

CVE-2026-40818 is an unauthenticated SQL Injection vulnerability in the _mb24confi_getDevice function. The flaw stems from improper neutralization of special elements used in a SQL SELECT command [CWE-89]. A remote attacker can send crafted input over the network to manipulate database queries without requiring authentication or user interaction. Successful exploitation results in a total loss of confidentiality, exposing sensitive data stored in the backend database. The vulnerability was disclosed through a CERT-VDE security advisory and is tracked under VDE-2026-044.

Critical Impact

Unauthenticated remote attackers can extract sensitive database contents by injecting SQL syntax into the vulnerable _mb24confi_getDevice function, resulting in complete confidentiality compromise.

Affected Products

Affected product details are published by CERT-VDE. Refer to the CERT-VDE Security Advisory VDE-2026-044 for the authoritative list of impacted devices and firmware versions.

Discovery Timeline

• 2026-05-27 - CVE-2026-40818 published to NVD
• 2026-05-27 - Last updated in NVD database

Technical Details for CVE-2026-40818

Vulnerability Analysis

The vulnerability resides in the _mb24confi_getDevice function, which constructs a SQL SELECT statement using attacker-controlled input. The function fails to properly neutralize special SQL metacharacters before incorporating user-supplied data into the query string. This classic SQL Injection pattern [CWE-89] allows an attacker to break out of the intended query context and append arbitrary SQL syntax.

Because the endpoint exposing _mb24confi_getDevice does not require authentication, exploitation requires only network reachability to the affected service. The attack complexity is low and no user interaction is needed. The impact is scoped to confidentiality, meaning attackers can read arbitrary database records but cannot directly modify data or disrupt service through this specific flaw.

Root Cause

The root cause is the absence of parameterized queries or input sanitization in _mb24confi_getDevice. User input flows directly into a dynamically constructed SQL SELECT statement. Special characters such as single quotes, comment sequences, and UNION keywords are passed through unfiltered, allowing query structure manipulation.

Attack Vector

An attacker sends a crafted HTTP request containing malicious SQL payloads to the network-accessible endpoint that invokes _mb24confi_getDevice. The injected payload typically uses UNION SELECT clauses or boolean-based blind techniques to extract data from arbitrary tables, including credential stores, configuration tables, and device inventories.

No verified proof-of-concept code is publicly available. Refer to the CERT-VDE Security Advisory for vendor-supplied technical details.

Detection Methods for CVE-2026-40818

Indicators of Compromise

• Inbound HTTP requests to endpoints invoking _mb24confi_getDevice containing SQL metacharacters such as ', --, ;, or UNION SELECT.
• Unusually long query strings or POST bodies targeting device configuration endpoints.
• Database query logs showing malformed or anomalous SELECT statements originating from the application service account.
• Spikes in outbound data volume from the affected device following suspicious inbound requests.

Detection Strategies

• Deploy web application firewall (WAF) signatures that flag SQL Injection patterns targeting device management endpoints.
• Enable database query logging and alert on syntactically anomalous queries originating from the _mb24confi_getDevice code path.
• Correlate network IDS alerts for SQL Injection signatures with access logs for the affected service.

Monitoring Recommendations

• Monitor authentication-free endpoints for repeated requests from a single source within short time windows.
• Baseline normal query patterns against the backend database and alert on deviations consistent with data extraction.
• Capture and retain full HTTP request payloads for forensic review of any suspicious activity.

How to Mitigate CVE-2026-40818

Immediate Actions Required

• Restrict network access to the affected service using firewall rules or network segmentation until a patch is applied.
• Review the CERT-VDE Security Advisory VDE-2026-044 for vendor-specific guidance and fixed firmware versions.
• Audit database and application logs for evidence of prior exploitation attempts against _mb24confi_getDevice.

Patch Information

Consult the CERT-VDE Security Advisory VDE-2026-044 for the vendor's patch availability and remediation instructions. No NVD-listed vendor advisory URLs are currently associated with this CVE beyond the CERT-VDE reference.

Workarounds

• Place the affected device behind a reverse proxy or WAF that enforces strict input validation on requests reaching device management endpoints.
• Apply network-layer access control lists to limit exposure of the vulnerable service to trusted administrative networks only.
• Disable the vulnerable endpoint if the device configuration permits and the functionality is not operationally required.

# Example: restrict access to the affected service to a trusted management subnet
iptables -A INPUT -p tcp --dport <service_port> -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport <service_port> -j DROP