The SpeedyCache – Cache, Optimization, Performance plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 1.4.2 via the 'comment_author_*, comment_author_email_*' parameter. This makes it possible for unauthenticated attackers to extract the full name and email address of returning commenters pre-filled into comment form input fields and persisted as the site-wide cached page by any unauthenticated attacker requesting the same public URL. The read-side handler in advanced-cache.php correctly skips cached delivery for requests carrying comment_author_* cookies, but this check is absent on the write path, meaning the cache poisoning is invisible to the victim commenter yet fully exploitable by any unauthenticated attacker with no cookies.
https://plugins.trac.wordpress.org/changeset/3734609/speedycache
https://plugins.trac.wordpress.org/changeset/3734608/speedycache/trunk/main/cache.php
https://plugins.trac.wordpress.org/browser/speedycache/tags/1.4.2/main/cache.php#L91
https://plugins.trac.wordpress.org/browser/speedycache/tags/1.4.2/main/cache.php#L214
https://plugins.trac.wordpress.org/browser/speedycache/tags/1.4.2/main/cache.php#L151
https://plugins.trac.wordpress.org/browser/speedycache/tags/1.4.2/main/advanced-cache.php#L108