CVE-2026-40813: Unauthenticated SQL Injection Vulnerability

CVE-2026-40813 Overview

CVE-2026-40813 is an unauthenticated SQL Injection vulnerability affecting the getLiveValues function. The flaw exists in the tagid parameter, which fails to properly neutralize special elements passed into a SQL SELECT statement. A remote attacker can send crafted requests over the network without authentication or user interaction. Successful exploitation results in a total loss of confidentiality of database contents. The issue is classified under CWE-89: Improper Neutralization of Special Elements used in an SQL Command. The advisory was coordinated through CERT-VDE, indicating exposure in industrial or operational technology software.

Critical Impact
Unauthenticated remote attackers can extract sensitive database records via the tagid parameter, resulting in complete confidentiality compromise.

Affected Products

Specific affected product details are published in the CERT-VDE Security Advisory VDE-2026-044
Vendor and product names were not included in the NVD record at publication time
Refer to the CERT-VDE advisory for impacted versions and firmware

Discovery Timeline

2026-05-27 - CVE-2026-40813 published to NVD
2026-05-27 - Last updated in NVD database

Technical Details for CVE-2026-40813

Vulnerability Analysis

The vulnerability resides in the getLiveValues function, which retrieves live telemetry or tag data from a backend database. The function accepts a tagid parameter supplied by the client and concatenates it into a SQL SELECT statement without sanitization or parameterization. An attacker can inject arbitrary SQL syntax through this parameter to alter query logic. Because the endpoint requires no authentication, exploitation does not depend on credential theft or social engineering. The vulnerability scope is limited to confidentiality, indicating attackers can read database contents but cannot modify data or impact availability through this flaw alone.

Root Cause

The root cause is improper neutralization of special elements within a SQL command [CWE-89]. The getLiveValues function constructs its query through string concatenation instead of using prepared statements or parameter binding. Characters such as single quotes, semicolons, and SQL keywords pass directly into the query parser. Standard SQL injection techniques including UNION-based extraction and boolean-based blind injection apply.

Attack Vector

The attack vector is network-based with low complexity. An attacker sends an HTTP or application-layer request to the endpoint exposing getLiveValues and supplies a malicious payload in the tagid parameter. Typical payloads append UNION SELECT clauses to enumerate tables, columns, and row data. Blind injection techniques work where output is not directly reflected. The CERT-VDE coordination suggests the affected component is reachable in industrial control system environments, where SCADA historians and HMI servers commonly expose tag-query interfaces. Refer to the CERT-VDE Security Advisory for vendor-specific exploitation context.

Detection Methods for CVE-2026-40813

Indicators of Compromise

HTTP or API requests to endpoints invoking getLiveValues containing SQL metacharacters such as ', --, ;, or UNION inside the tagid parameter
Unusual SELECT query patterns in database audit logs originating from the application service account, especially queries referencing information_schema or system catalogs
Spikes in outbound response sizes from the affected endpoint, consistent with bulk data extraction
Repeated requests with incrementing or boolean-style tagid values indicating blind SQL injection enumeration

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the tagid parameter for SQL syntax tokens
Enable database query logging and alert on queries containing UNION operations or system table references from the application context
Correlate unauthenticated requests to getLiveValues with subsequent anomalous database read volume
Hunt for long-duration sessions issuing many sequential parameterized requests to the same endpoint

Monitoring Recommendations

Forward application, web server, and database logs to a central analytics platform for correlation
Baseline normal getLiveValues request volume and alert on deviations
Monitor egress traffic from servers hosting the affected application for unusual data transfers
Track authentication-less access patterns to internal management endpoints

How to Mitigate CVE-2026-40813

Immediate Actions Required

Review the CERT-VDE Security Advisory VDE-2026-044 and apply the vendor-supplied patch or firmware update
Restrict network access to the affected service using firewall rules or network segmentation, allowing only trusted management hosts
Audit database logs for evidence of prior exploitation, focusing on queries referencing the tagid field
Rotate any database credentials that may have been exposed through the affected query context

Patch Information

Vendor patch details are published in the CERT-VDE Security Advisory VDE-2026-044. Apply the fixed version identified by the vendor as soon as operationally feasible. Coordinate maintenance windows for industrial systems to avoid disrupting production processes.

Workarounds

Place the affected application behind a reverse proxy or WAF that blocks SQL metacharacters in the tagid parameter
Isolate the system on a dedicated VLAN with strict access control lists until the patch is applied
Disable the getLiveValues endpoint if it is not required for operational use
Require VPN or jump-host access for any client that must reach the management interface

bash

# Example WAF rule (ModSecurity) to block SQL metacharacters in tagid
SecRule ARGS:tagid "@rx (?i)(union|select|--|;|'|\")" \
    "id:1040813,phase:2,deny,status:403,\
    msg:'CVE-2026-40813 SQLi attempt in tagid parameter'"