CVE-2026-2357: 
WordPress vulnerability analysis and mitigation

CVE-2026-2357 is a Stored Cross-Site Scripting (XSS) vulnerability in the Bold Page Builder plugin for WordPress, affecting all versions up to and including 5.6.8. The flaw exists in the plugin's bt_bb_shortcode shortcode handler, where insufficient input sanitization and output escaping on user-supplied attributes allow authenticated attackers with contributor-level access or above to inject arbitrary web scripts into pages. It was published on August 16, 2026, and carries a CVSS v3.1 base score of 6.4 (Medium) (GitHub Advisory, Wordfence).

The root cause is CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically insufficient sanitization of user-supplied shortcode attributes passed to the bt_bb_shortcode shortcode before they are rendered in page output (GitHub Advisory). An attacker with at least contributor-level WordPress access can craft a malicious shortcode attribute containing JavaScript, which is then stored in the database and executed in the browsers of any user who visits the affected page. No user interaction beyond page access is required for the payload to execute, and the scope is changed — meaning the injected script runs in the context of the victim's browser session rather than the plugin itself (Wordfence). No public proof-of-concept exploit code has been identified at this time.

Successful exploitation allows an authenticated contributor (or higher-privileged user) to permanently store malicious JavaScript in WordPress pages, which executes in the browsers of all subsequent visitors. This can result in session hijacking via cookie theft, credential harvesting, unauthorized actions performed on behalf of victims (including administrators), and redirection to malicious external sites (GitHub Advisory, Wordfence). If an administrator visits an injected page, the attacker could potentially escalate privileges or achieve full site compromise. Availability is not directly impacted.

There is no evidence of active in-the-wild exploitation or publicly available proof-of-concept code as of the time of disclosure (Wordfence). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.187%, placing it in the 8th percentile for exploitation likelihood within 30 days (GitHub Advisory). Exploitation requires authenticated access at the contributor level or above, which limits the attack surface compared to unauthenticated vulnerabilities.

1. Gain Contributor Access: Register or compromise a WordPress account with at least contributor-level privileges on a target site running Bold Page Builder ≤ 5.6.8.
2. Create or Edit a Page: Navigate to the WordPress editor and create or edit a page that uses the Bold Page Builder plugin.
3. Inject Malicious Shortcode: Insert a bt_bb_shortcode shortcode with a crafted attribute containing a JavaScript payload, for example: [bt_bb_shortcode attribute="\"onmouseover=\"alert(document.cookie)"] or an equivalent attribute-based XSS vector that bypasses the insufficient sanitization.
4. Publish the Page: Save and publish the page, causing the malicious payload to be stored in the WordPress database.
5. Trigger Execution: When any user (including administrators) visits the injected page, the stored JavaScript executes in their browser, enabling cookie theft, session hijacking, or further malicious actions (GitHub Advisory, Wordfence).

• Logs: WordPress audit logs showing contributor or author accounts creating or editing pages with bt_bb_shortcode shortcodes containing unusual attribute values (e.g., event handlers like onerror, onload, onmouseover, or encoded script tags).
• Database: WordPress wp_posts or wp_postmeta tables containing bt_bb_shortcode entries with JavaScript payloads or HTML event attributes in shortcode parameters.
• Network: Outbound requests from victim browsers to unknown external domains shortly after visiting pages containing Bold Page Builder content, potentially indicating data exfiltration (e.g., cookie or session token theft).
• File System: No direct file system artifacts expected for stored XSS; however, unexpected changes to page content in the WordPress admin panel may indicate tampering.
• Process/Behavior: Browser developer console errors or unexpected redirects occurring on pages rendered with the Bold Page Builder plugin.

The primary remediation is to update the Bold Page Builder plugin to a version newer than 5.6.8, which includes the fix committed to the WordPress plugin repository (WordPress Plugin Changeset). As an interim measure, restrict contributor and author-level access to only fully trusted users, and consider deploying a Web Application Firewall (WAF) to filter malicious script injections. Implementing Content Security Policy (CSP) headers can also reduce the impact of any successful XSS by limiting script execution sources (Wordfence). Regularly audit page content and user activity logs for unauthorized shortcode modifications.

Wordfence, which discovered and reported the vulnerability, included it in their weekly WordPress vulnerability report for August 10–16, 2026 (Wordfence Blog). The vulnerability received standard automated coverage across CVE aggregation platforms (VulDB, Vulners, CIRCL, ENISA EUVD) but no notable independent researcher commentary or significant social media discussion has been identified beyond routine CVE notification channels.