CVE-2024-43117: Wpmudev Hummingbird CSRF Vulnerability

CVE-2024-43117 Overview

CVE-2024-43117 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the WPMU DEV Hummingbird performance plugin for WordPress. The flaw impacts all versions of hummingbird-performance from initial release through version 3.9.1. An attacker can craft a malicious web page that, when visited by an authenticated WordPress administrator, triggers unauthorized state-changing actions on the target site. The vulnerability is categorized under CWE-352 and requires user interaction to succeed.

Critical Impact

Successful exploitation allows attackers to perform privileged actions on behalf of an authenticated administrator, potentially compromising site configuration, performance settings, and cached content integrity.

Affected Products

• WPMU DEV Hummingbird plugin for WordPress versions up to and including 3.9.1
• WordPress sites running the hummingbird-performance plugin
• All deployments with administrators who can be socially engineered into visiting attacker-controlled pages

Discovery Timeline

• 2024-08-26 - CVE-2024-43117 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2024-43117

Vulnerability Analysis

The Hummingbird plugin provides caching, asset optimization, and performance tuning for WordPress. The vulnerability stems from missing or improperly validated anti-CSRF tokens on plugin endpoints that perform state-changing operations. Without a valid nonce check, the plugin accepts forged requests that originate from external sites as if they were legitimate administrative actions.

An attacker hosts a malicious page containing an auto-submitting form or background request targeting a Hummingbird endpoint. When an authenticated WordPress administrator visits the page, the browser automatically includes the session cookie. The plugin executes the request under the administrator's privileges.

The attack succeeds because the request originates from the victim's authenticated browser session. The vulnerability impacts confidentiality, integrity, and availability when chained with administrator-level configuration changes.

Root Cause

The root cause is the absence or inadequate verification of WordPress nonces (wp_verify_nonce) and referrer checks on sensitive plugin actions. WordPress provides nonce primitives precisely to mitigate CSRF, but the plugin code paths through version 3.9.1 did not consistently enforce these checks.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker must lure an authenticated administrator to a crafted page or embed a CSRF payload in a context the administrator will load. No prior privileges are required on the target WordPress site.

The vulnerability manifests in plugin action handlers that mutate configuration or trigger plugin operations without nonce validation. See the Patchstack Vulnerability Report for additional technical context.

Detection Methods for CVE-2024-43117

Indicators of Compromise

• Unexpected changes to Hummingbird plugin settings, cache configuration, or asset optimization rules without corresponding administrator activity in audit logs
• HTTP POST requests to wp-admin/admin.php or admin-ajax.php containing Hummingbird action parameters with Referer headers pointing to external domains
• Administrator session activity originating from pages that subsequently triggered plugin configuration changes

Detection Strategies

• Monitor WordPress access logs for requests to Hummingbird endpoints with missing, invalid, or absent _wpnonce query parameters
• Correlate administrator authentication events with subsequent plugin configuration changes to identify out-of-band modifications
• Inspect HTTP Referer and Origin headers on state-changing requests to plugin handlers for cross-origin sources

Monitoring Recommendations

• Enable WordPress audit logging through a security plugin to capture all administrator-initiated configuration changes
• Forward web server access logs to a centralized logging platform and alert on Hummingbird action requests with anomalous referrer values
• Track plugin version inventory across WordPress installations to identify hosts still running versions at or below 3.9.1

How to Mitigate CVE-2024-43117

Immediate Actions Required

• Update the Hummingbird plugin to a version newer than 3.9.1 through the WordPress plugin dashboard or by deploying the latest release from the official WPMU DEV channel
• Audit recent administrator activity and plugin configuration changes for evidence of unauthorized modifications
• Force re-authentication for all WordPress administrators and rotate any session-related secrets if compromise is suspected

Patch Information

WPMU DEV addressed the vulnerability in releases after 3.9.1. Site operators should consult the Patchstack Vulnerability Report for the fixed version and apply the update through the standard WordPress plugin update workflow.

Workarounds

• Restrict administrative access to WordPress to trusted networks using IP allowlisting at the web server or WAF layer until the patch is applied
• Train administrators to avoid clicking untrusted links or browsing unrelated sites while authenticated to the WordPress admin panel
• Deploy a Web Application Firewall rule that requires a same-origin Referer header on requests to wp-admin/admin-ajax.php and Hummingbird action endpoints

# Example WAF rule logic to enforce same-origin Referer on Hummingbird actions
# (adapt to your WAF syntax)
if request.uri matches "/wp-admin/(admin-ajax|admin)\.php" 
   and request.body contains "action=wphb_" 
   and request.headers.Referer not starts_with "https://your-wordpress-site.example":
    block