Thrive Optimize - Authentication Bypass (CVE-2021-24219)
99Exploiting IPs reported
The Thrive Optimize WordPress plugin before 1.4.13.3, Thrive Comments WordPress plugin before 1.4.15.3, Thrive Headline Optimizer WordPress plugin before 1.3.7.3, Thrive Leads WordPress plugin before 2.3.9.4, Thrive Ultimatum WordPress plugin before 2.3.9.4, Thrive Quiz Builder WordPress plugin before 2.3.9.4, Thrive Apprentice WordPress plugin before 2.3.9.4, Thrive Visual Editor WordPress plugin before 2.6.7.4, Thrive Dashboard WordPress plugin before 2.3.9.3, Thrive Ovation WordPress plugin before 2.4.5, Thrive Clever Widgets WordPress plugin before 1.57.1 and Rise by Thrive Themes WordPress theme before 2.0.0, Ignition by Thrive Themes WordPress theme before 2.0.0, Luxe by Thrive Themes WordPress theme before 2.0.0, FocusBlog by Thrive Themes WordPress theme before 2.0.0, Minus by Thrive Themes WordPress theme before 2.0.0, Squared by Thrive Themes WordPress theme before 2.0.0, Voice WordPress theme before 2.0.0, Performag by Thrive Themes WordPress theme before 2.0.0, Pressive by Thrive Themes WordPress theme before 2.0.0, Storied by Thrive Themes WordPress theme before 2.0.0, Thrive Themes Builder WordPress theme before 2.2.4 register a REST API endpoint associated with Zapier functionality. While this endpoint was intended to require an API key in order to access, it was possible to access it by supplying an empty api_key parameter in vulnerable versions if Zapier was not enabled. Attackers could use this endpoint to add arbitrary data to a predefined option in the wp_options table.
CrowdSec analysis
CVE-2021-24219 is a vulnerability affecting multiple Thrive Themes WordPress plugins and themes, where a REST API endpoint intended for Zapier integration could be accessed without proper authentication by supplying an empty API key. This flaw allows unauthenticated attackers to add arbitrary data to a predefined option in the WordPress wp_options table, potentially leading to unauthorized configuration changes or data manipulation. Exploiting this vulnerability could enable attackers to tamper with site settings or introduce malicious data, impacting the integrity of affected WordPress sites.
CrowdSec has been tracking this vulnerability and its exploits since 15th of October 2025.
CrowdSec network observations suggest that most exploitation of CVE-2021-24219 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental. CrowdSec data also reveals a clear uptick in attacks involving CVE-2021-24219 over the past week. Activity is above the usual baseline, suggesting growing attention from attackers. This may reflect rising awareness, recent exploit releases, or expanded targeting efforts.
Attackers exploit the unauthenticated /wp-json/td/v1/optin/subscription REST API endpoint by sending POST requests with an empty api_key parameter, allowing arbitrary updates to WordPress options without proper authorization.
Exploitation
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Common Weakness Enumeration (CWE)
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Blocklist
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