CVE-2026-9855

Custom Field Template <= 2.7.8 - Authenticated (Contributor+) SQL Injection via 'post_ID' Parameter

2026-09-18 18:50
Luc Huynh from Noventiq RedTeam

Strategic Overview

Status
Patched in 2.8
Affected Plugin
Custom Field Template
Affected Version
<= 2.7.8
CVSS
6.5Medium
Weakness type
CWE-89 · Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
CVE
CVE-2026-9855
View all Custom Field Template vulnerabilities

At a glance

CVE-2026-9855 is a medium-severity Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') vulnerability in the Custom Field Template WordPress plugin, affecting versions <= 2.7.8. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity; high confidentiality impact). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 2.8; sites on affected versions should update now. Disclosed September 2026, reported by Luc Huynh from Noventiq RedTeam.

Vulnerability Overview

The Custom Field Template plugin for WordPress is vulnerable to generic SQL Injection via the 'post_ID' parameter in all versions up to, and including, 2.7.8 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 contributor-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. The capability check via current_user_can('edit_post', $id) is bypassable because WordPress internally casts $id to an integer for the permission evaluation while the full unsanitized string is preserved and passed to the SQL sink, and a valid nonce — which is also required — can be legitimately obtained by any Contributor-level user from the post edit screen.

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')

Custom Field Template <= 2.7.8 carries this weakness at post_ID, and reaching it takes an account at Contributor 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 Custom Field Template the fix is 2.8: builds <= 2.7.8 are affected, anything from 2.8 onward is not.

Remediation

Update to version 2.8, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor 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: Custom Field Template 2.8 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-9855https://www.wordfence.com/threat-intel/vulnerabilities/id/ce924708-935a-45c0-8959-dd122632cef4https://nvd.nist.gov/vuln/detail/CVE-2026-9855

Related records

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