CVE-2026-54811: WP eMember SQL Injection Vulnerability

CVE-2026-54811 Overview

CVE-2026-54811 is an unauthenticated SQL Injection vulnerability affecting the WP eMember WordPress plugin in versions prior to 10.9.4. The flaw allows remote attackers to inject arbitrary SQL statements into backend database queries without prior authentication. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

With a network attack vector, no privileges required, and no user interaction needed, exploitation is straightforward for remote attackers. The scope-changed impact means a successful attack can affect components beyond the vulnerable plugin itself, including the host WordPress database.

Critical Impact
Unauthenticated attackers can execute arbitrary SQL queries against the WordPress database, enabling data extraction, member account manipulation, and downstream compromise of site integrity.

Affected Products

WP eMember WordPress plugin versions prior to 10.9.4
WordPress sites running vulnerable WP eMember installations
Membership-driven WordPress deployments using WP eMember for access control

Discovery Timeline

2026-06-17 - CVE-2026-54811 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-54811

Vulnerability Analysis

The vulnerability stems from improper neutralization of user-supplied input within SQL statements processed by the WP eMember plugin. Attacker-controlled parameters reach database query construction without adequate sanitization or parameterization. This allows injection of SQL syntax that alters the intended query logic.

Because the affected entry points do not require authentication, any remote actor with network reachability to the WordPress site can interact with the vulnerable endpoints. The CVSS scope change indicates the impact crosses the security boundary of the plugin into the broader WordPress database context.

The EPSS probability of 0.291% places exploitation likelihood in the lower percentile range at the time of publication, but unauthenticated SQL injection flaws in WordPress plugins historically attract opportunistic scanning shortly after disclosure.

Root Cause

The root cause is the construction of SQL queries using concatenated user input rather than prepared statements with bound parameters. WordPress provides the $wpdb->prepare() API for safe query construction, and failure to use it consistently across plugin endpoints leads to injection conditions like this one.

Attack Vector

An attacker sends a crafted HTTP request to a vulnerable WP eMember endpoint, embedding SQL metacharacters or query fragments within parameters that flow into database operations. The injected payload modifies the resulting query, allowing extraction of arbitrary records, conditional logic abuse for blind injection, or manipulation of returned data sets.

For technical specifics of the affected parameter and endpoint, refer to the Patchstack WP eMember Vulnerability advisory.

Detection Methods for CVE-2026-54811

Indicators of Compromise

HTTP requests to WP eMember plugin endpoints containing SQL metacharacters such as ', UNION SELECT, SLEEP(, or -- in query parameters or POST bodies
Unexpected slow response times on WP eMember endpoints, indicative of time-based blind SQL injection probing
Database error messages surfaced in HTTP responses referencing wp_ table prefixes or MySQL syntax errors
New or modified rows in WP eMember member tables that do not correlate with legitimate registration activity

Detection Strategies

Inspect WordPress and web server access logs for repeated requests to /wp-content/plugins/wp-emember/ paths containing encoded SQL syntax
Deploy web application firewall (WAF) rules targeting SQL injection patterns directed at WP eMember endpoints
Monitor database query logs for anomalous UNION, SELECT from wp_users, or unusually long queries originating from the WordPress application user

Monitoring Recommendations

Enable verbose logging on the WordPress application layer and forward logs to a centralized analytics platform for correlation
Track outbound traffic from the WordPress host for signs of data exfiltration following suspicious inbound activity
Alert on administrative role changes or new user creations within WordPress that occur outside of expected workflows

How to Mitigate CVE-2026-54811

Immediate Actions Required

Upgrade WP eMember to version 10.9.4 or later on all affected WordPress instances
Audit existing member records and administrator accounts for unauthorized additions or modifications
Rotate WordPress administrator credentials and database passwords if compromise is suspected
Review web server and database logs for prior exploitation attempts against WP eMember endpoints

Patch Information

The vendor has addressed the issue in WP eMember version 10.9.4. Site administrators should apply the update through the WordPress plugin manager or by replacing plugin files manually. Refer to the Patchstack advisory for vendor remediation details.

Workarounds

Temporarily disable the WP eMember plugin until patching is feasible
Deploy WAF signatures that block SQL injection patterns targeting WP eMember request paths
Restrict access to membership-related URLs by IP allowlist where membership functionality is only required for known sources
Enforce least-privilege on the WordPress database user to limit the blast radius of any successful injection

bash

# Update WP eMember via WP-CLI to the patched version
wp plugin update wp-emember --version=10.9.4

# Verify installed version
wp plugin get wp-emember --field=version

# Temporary mitigation: deactivate the plugin until patched
wp plugin deactivate wp-emember