The EWWW Image Optimizer WordPress plugin before 8.8.0 does not prevent authenticated users with author-level permissions from storing a serialized value in a post meta field that is deserialized when the post is rendered, allowing them to perform PHP Object Injection, which can lead to remote code execution when a suitable gadget chain is present via another installed EWWW Image Optimizer WordPress plugin before 8.8.0 or .

The EWWW Image Optimizer WordPress plugin before 8.8.0 does not confine a WebP-derivative file migration routine to the current site's own uploads directory, letting an attacker with Administrator-level access rename or delete existing WebP-derivative image files outside that scope, including, on a multisite network, files belonging to a different site they have no access to.

Contributor Cross Site Scripting (XSS) in EWWW Image Optimizer <= 8.7.7 versions.

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Exactly WWW EWWW Image Optimizer. It works only when debug.log is turned on.This issue affects EWWW Image Optimizer: from n/a through 7.2.0.

The EWWW Image Optimizer plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 5.8.1. This is due to missing or incorrect nonce validation on the ewwwnggbulkinit() function. This makes it possible for unauthenticated attackers to perform bulk image optimization via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

EWWW Image Optimizer before 2.8.5 allows remote command execution because it relies on a protection mechanism involving boolval, which is unavailable before PHP 5.5.