CVE-2026-18387

Groundhogg <= 4.5.14 - Authenticated (Vendor+) SQL Injection via 'tag_query' Parameter

2026-08-14 15:11
Jonathan Dersch

Strategic Overview

Status
Patched in 4.5.15
Affected Plugin
Groundhogg — CRM, Newsletters, and Marketing Automation
Affected Version
<= 4.5.14
CVSS
6.5Medium
Weakness type
CWE-89 · Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
CVE
CVE-2026-18387
View all Groundhogg — CRM, Newsletters, and Marketing Automation vulnerabilities

At a glance

CVE-2026-18387 is a medium-severity Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') vulnerability in the Groundhogg WordPress plugin, affecting versions <= 4.5.14. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity; high confidentiality impact). Exploitation requires an authenticated account at Vendor level or above. The issue is fixed in version 4.5.15; sites on affected versions should update now. Disclosed August 2026, reported by Jonathan Dersch.

Vulnerability Overview

The Groundhogg — CRM, Newsletters, and Marketing Automation plugin for WordPress is vulnerable to generic SQL Injection via the 'tag_query' parameter in all versions up to, and including, 4.5.14 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for authenticated attackers, with vendor-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. Exploitation requires the attacker to trigger the vulnerable Legacy_Contact_Query code path by submitting an unknown filter type (e.g. filters[0][0][type]=force_fallback), which causes a FilterException that dispatches execution away from the modern query handler.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality.

CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Groundhogg <= 4.5.14 carries this weakness at tag_query, and reaching it takes an account at Vendor level or above. SQL injection happens when request data is concatenated into a query instead of being bound as a parameter, letting an attacker change the structure of the statement rather than just its values.

A working injection can read any table the database user can see, which on a WordPress install means user records, password hashes and session or API secrets stored in options. For Groundhogg the fix is 4.5.15: builds <= 4.5.14 are affected, anything from 4.5.15 onward is not.

Remediation

Update to version 4.5.15, or a newer patched version

How does WordSec protect against this?

An attacker needs Vendor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Groundhogg 4.5.15 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-18387https://www.wordfence.com/threat-intel/vulnerabilities/id/04881aac-9d3b-48c0-b095-e91797df46e3https://nvd.nist.gov/vuln/detail/CVE-2026-18387

Related records

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