CVE-2026-11784

Optimole – Optimize Images | Convert WebP & AVIF | CDN & Lazy Load | Image Optimization <= 4.2.6 - Cross-Site Request Forgery via 'optml_replace_file' AJAX Action

2026-06-17 00:00
Alexandru Bucur

Strategic Overview

Status
Patched in 4.2.7
Affected Version
<= 4.2.6
CVSS
4.3Medium
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE-2026-11784
View all Optimole – Optimize Images | Convert WebP & AVIF | CDN & Lazy Load | Image Optimization vulnerabilities

At a glance

CVE-2026-11784 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Optimole WordPress plugin, affecting versions <= 4.2.6. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.2.7; sites on affected versions should update now. Disclosed June 2026, reported by Alexandru Bucur.

Vulnerability Overview

The Optimole – Optimize Images | Convert WebP & AVIF | CDN & Lazy Load | Image Optimization plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 4.2.6. This is due to missing or incorrect nonce validation on the replace_file function. This makes it possible for unauthenticated attackers to overwrite existing media attachments with attacker-supplied file content by supplying a forged multipart POST request targeting any attachment the victim has edit_post capability over via a forged request granted they can trick a site administrator into performing an action such as clicking on a link. The forged request requires a victim with at least Author-level privileges, as the handler enforces a current_user_can('edit_post', $id) check; tricking an Author-level or higher user into clicking a crafted link is sufficient to trigger the overwrite against attachments that user can edit.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-352: Cross-Site Request Forgery (CSRF)

Optimole <= 4.2.6 carries this weakness at edit_post, and reaching it takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.

An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For Optimole the fix is 4.2.7: builds <= 4.2.6 are affected, anything from 4.2.7 onward is not.

Remediation

Update to version 4.2.7, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Optimole: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Optimole 4.2.7 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

Related records

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