CVE-2025-39573: WP Posts Carousel Stored XSS Vulnerability

CVE-2025-39573 Overview

CVE-2025-39573 is a stored cross-site scripting (XSS) vulnerability in the teastudio.pl WP Posts Carousel plugin for WordPress. The flaw affects all versions up to and including 1.3.10. An authenticated attacker with low privileges can inject malicious scripts that persist in the database and execute in the browsers of other users who view affected pages.

The vulnerability is categorized as [CWE-79], Improper Neutralization of Input During Web Page Generation. Exploitation requires user interaction and crosses a security scope boundary, which allows the injected script to affect resources beyond the attacker's initial authorization context.

Critical Impact
An authenticated contributor-level or higher user can store JavaScript payloads that execute in administrator sessions, enabling session theft, account takeover, or administrative action hijacking.

Affected Products

teastudio.pl WP Posts Carousel WordPress plugin versions through 1.3.10
WordPress installations with the wp-posts-carousel plugin enabled
Any site exposing carousel-rendered content to administrative or editorial users

Discovery Timeline

2025-04-16 - CVE-2025-39573 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-39573

Vulnerability Analysis

The WP Posts Carousel plugin fails to properly neutralize user-supplied input before it is rendered inside WordPress pages. Input accepted through plugin fields or shortcode attributes is stored in the database without adequate sanitization. When the carousel content is later rendered, the unsanitized data is written into the HTML response.

This behavior allows an attacker holding at least contributor-level credentials to persist arbitrary JavaScript on the site. Because the payload is stored, every subsequent page view that loads the carousel executes the attacker's script in the viewer's browser session. The scope change (CVSS S:C) reflects that the injected code runs in the browser context of other users, including administrators.

Root Cause

The root cause is missing or insufficient output encoding and input sanitization in the plugin's rendering pipeline. The plugin trusts data retrieved from storage and emits it directly into page markup. WordPress functions such as esc_html(), esc_attr(), or wp_kses_post() are not applied where user-controlled data reaches the DOM.

Attack Vector

An authenticated attacker with low privileges crafts carousel content, titles, or shortcode parameters containing JavaScript. The payload is saved through the plugin's normal workflow. When an administrator or other authenticated user opens a page containing the carousel, the browser parses and executes the script with that user's privileges.

Typical attacker goals include stealing authentication cookies, invoking privileged REST API endpoints via the victim's session, creating new administrator accounts, or planting backdoored plugins. Full technical details are available in the Patchstack XSS Vulnerability Report.

Detection Methods for CVE-2025-39573

Indicators of Compromise

Posts, pages, or carousel entries containing <script> tags, onerror=, onload=, or javascript: URIs in fields that normally contain plain text
Unexpected administrator account creation or privilege changes shortly after an administrator viewed a page rendering the plugin
Outbound HTTP requests from administrator browsers to unfamiliar domains following WordPress admin activity
Modifications to WordPress options, theme files, or plugin files not tied to a legitimate change window

Detection Strategies

Audit the wp_posts and plugin-specific tables for carousel entries containing HTML event handlers or script tags
Review access logs for POST requests to wp-admin/post.php or plugin editing endpoints from low-privilege accounts followed by administrator page views
Compare installed plugin versions against the fixed release and flag any wp-posts-carousel installation at or below version 1.3.10

Monitoring Recommendations

Enable WordPress audit logging to track content edits by contributor, author, and editor roles
Deploy a web application firewall rule set that blocks script injection patterns in POST bodies targeting plugin endpoints
Alert on new administrator account creation, role elevation, and changes to the siteurl or home options

How to Mitigate CVE-2025-39573

Immediate Actions Required

Update the WP Posts Carousel plugin to a version later than 1.3.10 as soon as the vendor publishes a fix
Review all existing carousel content for injected scripts and remove any malicious entries
Rotate WordPress administrator passwords and invalidate active sessions if suspicious activity is detected
Restrict contributor, author, and editor accounts to trusted users only until the plugin is patched

Patch Information

At the time of publication, the Patchstack advisory lists all versions through 1.3.10 as affected. Administrators should monitor the plugin's WordPress.org page and the Patchstack advisory for the fixed release and apply it immediately once available.

Workarounds

Deactivate and remove the WP Posts Carousel plugin until a patched version is released
Enforce a Content Security Policy that restricts inline script execution on administrative and public pages
Apply virtual patching through a web application firewall to filter script payloads submitted to plugin endpoints
Reduce the number of accounts with content-editing capabilities to limit the attacker population

bash

# Example: list and deactivate the vulnerable plugin with WP-CLI
wp plugin list --name=wp-posts-carousel --fields=name,status,version
wp plugin deactivate wp-posts-carousel