CVE-2024-43965: Smackcoders SendGrid SQLi Vulnerability

CVE-2024-43965 Overview

CVE-2024-43965 is an SQL Injection vulnerability in the Smackcoders SendGrid for WordPress plugin. The flaw affects all plugin versions up to and including 1.4. Attackers can exploit this issue over the network without authentication or user interaction, making it suitable for automated, large-scale targeting of vulnerable WordPress sites. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). Successful exploitation allows attackers to read, modify, or delete database contents, including WordPress user credentials and session data.

Critical Impact
Unauthenticated remote attackers can execute arbitrary SQL queries against the WordPress database, leading to full compromise of confidentiality, integrity, and availability.

Affected Products

Smackcoders SendGrid for WordPress plugin
All versions from n/a through 1.4
WordPress installations using the wp-sendgrid-mailer plugin

Discovery Timeline

2024-08-29 - CVE-2024-43965 published to NVD
2024-09-04 - Last updated in NVD database

Technical Details for CVE-2024-43965

Vulnerability Analysis

The vulnerability resides in the Smackcoders SendGrid for WordPress plugin, which integrates the SendGrid email delivery service with WordPress. User-supplied input reaches SQL query construction without proper sanitization or parameterization. Attackers can inject crafted SQL syntax into vulnerable request parameters and alter the intended query logic.

Because the issue requires no authentication and no user interaction, it can be exploited directly through HTTP requests to the plugin's endpoints. The attack vector is fully network-based, allowing remote exploitation against any reachable WordPress instance running the vulnerable plugin. The EPSS probability of 18.43% places this CVE in the 95th percentile for likelihood of exploitation activity.

Root Cause

The root cause is improper neutralization of special elements in SQL commands [CWE-89]. The plugin concatenates untrusted input into SQL statements rather than using prepared statements with parameter binding through the WordPress $wpdb->prepare() API. This allows characters such as single quotes, comments, and UNION operators to break out of the intended query context.

Attack Vector

An unauthenticated remote attacker sends crafted HTTP requests targeting vulnerable parameters processed by the plugin. By injecting SQL payloads, the attacker can extract sensitive data from the WordPress database, including the wp_users table containing administrator password hashes. Attackers can also escalate to remote code execution by writing malicious content to the database or chaining with other WordPress weaknesses.

The vulnerability is described in prose because no verified proof-of-concept code is publicly available. Refer to the Patchstack SQL Injection Vulnerability advisory for additional technical context.

Detection Methods for CVE-2024-43965

Indicators of Compromise

HTTP requests to plugin endpoints containing SQL metacharacters such as ', --, UNION SELECT, or SLEEP(
Unexpected database errors logged by WordPress or MySQL referencing plugin files under wp-content/plugins/wp-sendgrid-mailer/
New or modified administrator accounts in wp_users without legitimate provisioning records
Outbound connections from the web server to unfamiliar hosts following anomalous request activity

Detection Strategies

Inspect web server access logs for query strings or POST bodies containing SQL injection patterns targeting SendGrid plugin paths
Enable WordPress debug logging to capture SQL errors that indicate injection attempts
Deploy a Web Application Firewall (WAF) ruleset that flags SQL injection signatures against plugin endpoints
Correlate authentication anomalies with prior suspicious requests to the affected plugin

Monitoring Recommendations

Forward WordPress, web server, and database logs to a centralized analytics platform for correlation
Alert on database query volumes or error rates that deviate from baseline for the WordPress host
Monitor file integrity for changes to plugin files and the WordPress core under wp-admin/ and wp-includes/
Track outbound network traffic from the web server for signs of data exfiltration

How to Mitigate CVE-2024-43965

Immediate Actions Required

Identify all WordPress sites running the Smackcoders SendGrid for WordPress plugin at version 1.4 or earlier
Deactivate and remove the vulnerable plugin until a patched version is confirmed available from the vendor
Rotate WordPress administrator credentials and any API keys stored in the database
Review wp_users, wp_options, and recent post revisions for signs of unauthorized modification

Patch Information

At the time of NVD publication, the advisory lists affected versions through 1.4 without a confirmed fixed release. Consult the Patchstack advisory for the latest vendor response and patch availability before reinstalling the plugin.

Workarounds

Remove the plugin entirely and use an alternative SendGrid integration that receives active maintenance
Restrict access to WordPress admin and plugin endpoints by source IP address through web server or firewall rules
Deploy WAF virtual patching rules that block SQL injection payloads targeting the wp-sendgrid-mailer plugin path
Apply database account least-privilege by ensuring the WordPress database user cannot execute FILE or schema-altering operations beyond what the application requires

bash

# Configuration example: remove the vulnerable plugin via WP-CLI
wp plugin deactivate wp-sendgrid-mailer
wp plugin delete wp-sendgrid-mailer

# Example nginx rule to block obvious SQLi patterns on the plugin path
# location ~* /wp-content/plugins/wp-sendgrid-mailer/ {
#     if ($args ~* "(union.*select|sleep\(|--|';)") { return 403; }
# }