CVE-2026-40847: system_tag View SQL Injection Vulnerability

CVE-2026-40847 Overview

CVE-2026-40847 is a SQL injection vulnerability affecting the system_tag view of an unspecified product covered by CERT-VDE Security Advisory VDE-2026-044. The flaw stems from improper neutralization of special elements within a SQL SELECT command [CWE-89]. A remote attacker with low privileges can inject crafted SQL statements through the affected view. Successful exploitation results in a total loss of confidentiality of the underlying database contents. The advisory notes the issue as unauthenticated in nature, exposing sensitive records without further user interaction.

Critical Impact
A remote attacker can extract confidential database contents by injecting SQL through the system_tag view, leading to full disclosure of stored data.

Affected Products

Specific affected products are listed in the CERT-VDE advisory VDE-2026-044
Component: system_tag view
Vendor details: refer to the CERT-VDE advisory

Discovery Timeline

2026-05-27 - CVE CVE-2026-40847 published to NVD
2026-05-27 - Last updated in NVD database

Technical Details for CVE-2026-40847

Vulnerability Analysis

The vulnerability resides in the system_tag view, where user-controllable input flows into a SQL SELECT statement without proper sanitization or parameterization. An attacker submits crafted input containing SQL metacharacters that alter the structure of the executed query. The query engine then returns data the attacker is not authorized to read.

The Common Weakness Enumeration classifies this as [CWE-89] Improper Neutralization of Special Elements used in an SQL Command. The impact is restricted to confidentiality, with no direct integrity or availability impact reported. The attack is performed over the network and requires low attacker privileges. Because the underlying query is a SELECT, exploitation primarily enables data exfiltration through techniques such as UNION-based extraction, boolean-based blind injection, or time-based inference.

Root Cause

The root cause is the absence of input neutralization in the SQL query construction logic backing the system_tag view. User-supplied values are concatenated into a SELECT statement instead of being passed as bound parameters. This pattern allows attacker-supplied SQL fragments to be interpreted as code rather than data.

Attack Vector

The attack vector is network-based. An authenticated low-privileged user sends a crafted request to the endpoint exposing the system_tag view. The injected payload modifies the query to return arbitrary data from accessible tables. No user interaction is required to complete the attack.

Detailed exploitation techniques are not published. Refer to the CERT-VDE Security Advisory for vendor-supplied technical context.

Detection Methods for CVE-2026-40847

Indicators of Compromise

Web or application logs containing SQL metacharacters such as ', --, UNION SELECT, or SLEEP( in requests targeting the system_tag endpoint
Unusual SELECT query patterns originating from low-privileged accounts in database audit logs
Spikes in response size or response latency for requests interacting with system_tag

Detection Strategies

Enable database query logging and alert on queries referencing system_tag that include union operators, comment sequences, or sleep functions
Deploy a web application firewall with SQL injection signatures tuned to the affected endpoint
Correlate authentication events with anomalous query volume per low-privileged account

Monitoring Recommendations

Forward application and database logs to a centralized analytics platform for retention and correlation
Track per-user query volume baselines and alert on deviations
Monitor outbound network traffic from the application host for signs of bulk data exfiltration

How to Mitigate CVE-2026-40847

Immediate Actions Required

Review the CERT-VDE advisory VDE-2026-044 to identify affected product versions in your environment
Restrict network access to the affected management interface to trusted administrative networks
Audit accounts with low-privileged access and disable any that are unnecessary

Patch Information

Consult the CERT-VDE Security Advisory for vendor-supplied fixed versions and update procedures. Apply the vendor patch as soon as it is available in your change window.

Workarounds

Place the application behind a web application firewall with SQL injection rule sets enabled
Limit access to the system_tag view through network segmentation and access control lists
Rotate database credentials and review database role permissions to enforce least privilege

bash

# Example WAF rule concept - block common SQLi payloads against the affected path
# Adapt syntax to your WAF (ModSecurity, AWS WAF, etc.)
SecRule REQUEST_URI "@contains /system_tag" \
  "phase:2,deny,status:403,id:1004084,\
   chain,msg:'Potential SQLi against system_tag (CVE-2026-40847)'"
  SecRule ARGS "@rx (?i)(union(\s)+select|--|;|sleep\(|benchmark\()" "t:none"