Summary
CVE-2026-16603 is an unauthenticated sensitive information disclosure vulnerability in the Passster (Content Protector) WordPress plugin. Versions before 4.3.6 fail to enforce category-based content protection on the WordPress core REST API, allowing unauthenticated attackers to read protected post content. The issue is rated High severity (CVSS 7.5).
Technical details
- Root cause: The plugin does not enforce its category-based content protection at the WordPress core REST API layer, so access controls that apply to normal page rendering are not applied to REST API responses.
- Trigger conditions: An attacker queries the core REST API endpoints for posts that belong to a protected category; no authentication or user interaction is required.
- Attack vector: Network — remotely exploitable over HTTP against the site’s REST API.
- Impact: Unauthenticated disclosure of the full content, title, and excerpt of category-locked posts, breaking the intended content restriction.
Affected software
- Passster (Content Protector) WordPress plugin — all versions before 4.3.6.
Severity
- CVSS v3.1 base score: 7.5 (High)
- Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Mitigation and recommended actions
- Immediate: Update the Passster (Content Protector) plugin to version 4.3.6 or later.
- If no patch can be applied: Restrict or disable unauthenticated access to the WordPress REST API (for example, limit REST access to authenticated users), and place category-locked content behind additional access controls until the plugin is updated.
How IONIX identifies potentially affected assets
IONIX matches the following signals against data already collected when it crawled the asset; identifying the technology sends no request beyond that crawl.
- Raw response body:
/wp-content/plugins/content-protector/

