The Freemius SDK, as used by hundreds of WordPress plugin and theme developers, was vulnerable to Cross-Site Request Forgery and Information disclosure due to missing capability checks and nonce protection on the _get_debug_log, _get_db_option, and the _set_db_option functions in versions up to, and including 2.4.2. Any WordPress plugin or theme running a version of Freemius less than 2.4.3 is vulnerable.

The All in One SEO WordPress plugin before 4.6.1.1 does not validate and escape some of its Post fields before outputting them back, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks

The All in One SEO – Best WordPress SEO Plugin – Easily Improve SEO Rankings & Increase Traffic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's shortcode(s) in all versions up to, and including, 4.6.0 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The All in One SEO Pack plugin for WordPress is vulnerable to Stored Cross-Site Scripting via multiple parameters in versions up to, and including, 4.2.9 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with Contributor+ role to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The All in One SEO Pack plugin for WordPress is vulnerable to Stored Cross-Site Scripting via multiple parameters in versions up to, and including, 4.2.9 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with Administrator role or above to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Server Side Request Forgery (SSRF) vulnerability in All in One SEO Pro plugin <= 4.2.5.1 on WordPress.

Multiple Cross-Site Request Forgery (CSRF) vulnerabilities in All in One SEO plugin <= 4.2.3.1 at WordPress.

The All in One SEO WordPress plugin before 4.1.5.3 is affected by an authenticated SQL injection issue, which was discovered during an internal audit by the Jetpack Scan team, and could grant attackers access to privileged information from the affected site’s database (e.g., usernames and hashed passwords).

The All in One SEO WordPress plugin before 4.1.5.3 is affected by a Privilege Escalation issue, which was discovered during an internal audit by the Jetpack Scan team, and may grant bad actors access to protected REST API endpoints they shouldn’t have access to. This could ultimately enable users with low-privileged accounts, like subscribers, to perform remote code execution on affected sites.

The All in One SEO – Best WordPress SEO Plugin – Easily Improve Your SEO Rankings before 4.1.0.2 enables authenticated users with "aioseo_tools_settings" privilege (most of the time admin) to execute arbitrary code on the underlying host. Users can restore plugin's configuration by uploading a backup .ini file in the section "Tool > Import/Export". However, the plugin attempts to unserialize values of the .ini file. Moreover, the plugin embeds Monolog library which can be used to craft a gadget chain and thus trigger system command execution.