Apollo13 Framework Extension < 1.9.9 - Authenticated (Contributor+) Stored Cross-Site Scripting via `a13_alt_link` Parameter

Description

The Apollo13 Framework Extensions plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘a13_alt_link’ parameter in all versions up to, and including, 1.9.8 due to insufficient input sanitization and output escaping. 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.