CVE-2026-5097: wpForo Forum WordPress Plugin SQL Injection

CVE-2026-5097 Overview

The wpForo Forum plugin for WordPress contains a SQL injection vulnerability in the referer parameter, affecting all versions up to and including 2.4.17. The flaw stems from insufficient escaping of user-supplied input combined with inadequate preparation of the underlying SQL query. Unauthenticated attackers can append arbitrary SQL statements to existing queries, enabling extraction of sensitive data from the WordPress database. The issue is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). The vulnerability was addressed in wpForo version 3.0.0.

Critical Impact
Unauthenticated attackers can extract sensitive database contents, including user credentials, session data, and private forum posts, over the network with no user interaction.

Affected Products

wpForo Forum plugin for WordPress, all versions through 2.4.17
WordPress installations exposing the vulnerable referer parameter to unauthenticated requests
Sites that have not upgraded to wpForo 3.0.0 or later

Discovery Timeline

2026-08-28 - CVE-2026-5097 published to NVD
2026-08-28 - Last updated in NVD database

Technical Details for CVE-2026-5097

Vulnerability Analysis

The vulnerability resides in wpForo's handling of the referer request parameter within the plugin's core functions and revisions module. Vulnerable code paths are visible in includes/functions.php and modules/revisions/classes/Actions.php in the 2.4.16 tag on the WordPress plugin repository. The plugin concatenates the attacker-controlled referer value into SQL statements without invoking $wpdb->prepare() with proper placeholders, and without escaping the value with esc_sql() or a strict allowlist.

Because the injection point is reachable through unauthenticated requests, an attacker can perform UNION-based or boolean-based extraction against the WordPress database. Successful exploitation exposes rows from tables such as wp_users, session tokens, and wpForo-specific tables containing private discussions. The CVSS vector reflects confidentiality-only impact, meaning data disclosure is the primary risk while integrity and availability of the database are not directly affected by this flaw.

Root Cause

The root cause is a failure to apply parameterized queries to the referer parameter. WordPress provides $wpdb->prepare() for safe query construction, but the affected wpForo code paths interpolate the raw parameter directly into SQL strings. The escaping applied before the query executes is insufficient to neutralize SQL metacharacters in the injection context.

Attack Vector

The attack vector is network-based. An unauthenticated attacker crafts an HTTP request to a wpForo endpoint that processes the referer parameter and appends SQL payloads such as UNION SELECT clauses. The vulnerability manifests server-side and does not require user interaction. Technical details are documented in the Wordfence Vulnerability Report and can be traced through the WordPress wpForo Version Change diff between 2.4.17 and 3.0.0.

No verified public proof-of-concept code is available at the time of publication. See the vendor-linked source references for the exact vulnerable functions.

Detection Methods for CVE-2026-5097

Indicators of Compromise

HTTP requests to wpForo endpoints containing SQL syntax in the referer parameter, such as UNION SELECT, SLEEP(, --, /*, or information_schema references.
Web server access logs showing anomalously long referer values or URL-encoded SQL keywords targeting wpForo URLs.
Unexpected database read spikes or slow queries originating from wpForo-related PHP handlers.
New or unexplained access to wp_users or wpForo tables from application accounts.

Detection Strategies

Deploy a web application firewall (WAF) rule that inspects the referer HTTP header and query parameter for SQL injection patterns on wpForo routes.
Enable MySQL general query or slow query logging temporarily to surface unusual UNION or subquery patterns tied to wpForo requests.
Correlate WordPress access logs with database logs to identify request-to-query pairs that read authentication tables without an authenticated session.

Monitoring Recommendations

Alert on 200-status responses to unauthenticated wpForo endpoints paired with response body sizes that deviate from baselines.
Monitor for repeated requests from a single source that mutate the referer value with incremental payloads, indicative of boolean-based extraction.
Track outbound egress from the WordPress host for signs of data staging following suspected exploitation.

How to Mitigate CVE-2026-5097

Immediate Actions Required

Upgrade the wpForo Forum plugin to version 3.0.0 or later on every WordPress site where it is installed.
Audit web server and database logs for injection attempts against wpForo endpoints dating back to plugin installation.
Rotate WordPress administrator passwords, API keys, and secret keys in wp-config.php if exploitation is suspected.
Review wp_users and wpForo tables for unauthorized accounts or modified privileges.

Patch Information

The vendor resolved the SQL injection in wpForo 3.0.0. The remediation diff is available in the WordPress wpForo Version Change changeset. Site administrators should apply the update through the WordPress plugin dashboard or via WP-CLI. Additional context is available in the Wordfence Vulnerability Report.

Workarounds

If immediate patching is not feasible, deactivate the wpForo Forum plugin until the update can be applied.
Deploy a WAF signature that blocks SQL metacharacters in the referer parameter targeting wpForo URLs.
Restrict access to wpForo endpoints by IP allowlist at the reverse proxy where forum traffic is limited to known sources.

bash

# Update wpForo via WP-CLI
wp plugin update wpforo --version=3.0.0
wp plugin list --name=wpforo --fields=name,status,version