CVE-2026-18387: Groundhogg <= 4.5.14 - Authenticated (Vendor+) SQL Injection via 'tag_query' Parameter
The Groundhogg — CRM, Newsletters, and Marketing Automation plugin for WordPress is vulnerable to generic SQL Injection via the 'tagquery' 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 LegacyContactQuery code path by submitting an unknown filter type (e.g. filters[0][0][type]=forcefallback), which causes a FilterException that dispatches execution away from the modern query handler.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Groundhogg (WordPress plugin)to a version that resolves this vulnerability.Fixed in 4.5.14 - Compensating control
Mitigate exploitation by preventing authenticated users (vendor-level access and above) from triggering the Legacy_Contact_Query code path—specifically by blocking or rejecting requests that submit an unknown filter type in parameters like filters[0][0][type]=force_fallback.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-18387?
CVE-2026-18387 has a medium severity rating of 6.5.
How do I fix CVE-2026-18387?
To mitigate CVE-2026-18387, you should upgrade Groundhogg to version 4.5.15 or later.
What type of vulnerability is described in CVE-2026-18387?
CVE-2026-18387 describes an authenticated SQL injection vulnerability.
What parameter is exploited in CVE-2026-18387?
The vulnerability in CVE-2026-18387 is exploited through the 'tag_query' parameter.
Which versions of Groundhogg are affected by CVE-2026-18387?
All versions of Groundhogg up to and including 4.5.14 are affected by CVE-2026-18387.