CVE-2025-62871: 
WordPress vulnerability analysis and mitigation

CVE-2025-62871 is a Cross-Site Request Forgery (CSRF) vulnerability in the WordPress plugin "Just TinyMCE Custom Styles" (just-tinymce-styles) developed by Alex Prokopenko / JustCoded. It affects all versions from n/a through 1.2.1 and was reported by security researcher Nabil Irawan on November 8, 2025, with public disclosure on December 8–9, 2025. As of the time of disclosure, no official patch is available. The vulnerability carries a CVSS v3.1 base score of 4.3 (Medium) (Patchstack).

The vulnerability is classified as CWE-352 (Cross-Site Request Forgery) and maps to OWASP Top 10 category A1: Broken Access Control. The plugin fails to implement adequate CSRF protections (e.g., nonce verification) on sensitive administrative actions, allowing an unauthenticated attacker to craft a malicious request that, when executed by an authenticated privileged user (such as an administrator), performs unintended actions on the WordPress site. Exploitation requires social engineering to trick a logged-in user into visiting a crafted page or clicking a malicious link (Patchstack).

Successful exploitation allows a malicious actor to force higher-privileged WordPress users (e.g., administrators) to execute unwanted actions under their current authentication session, such as modifying TinyMCE custom style configurations. The confidentiality impact is none, availability impact is none, and integrity impact is low and scoped to the affected WordPress instance. While the individual impact is limited, Patchstack notes that CSRF vulnerabilities of this type are commonly leveraged in mass-exploit campaigns targeting thousands of WordPress sites simultaneously (Patchstack).

No public proof-of-concept exploit code or in-the-wild exploitation has been reported for CVE-2025-62871. The EPSS score is extremely low at approximately 0.008%, reflecting a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Patchstack rates the priority as "Low" and considers it unlikely to be actively exploited (Patchstack).

1. Reconnaissance: Identify WordPress sites running the Just TinyMCE Custom Styles plugin version 1.2.1 or earlier, using tools like WPScan or by inspecting publicly accessible plugin metadata.
2. Craft malicious request: Create an HTML page or form that automatically submits a forged HTTP request to the target WordPress site's administrative endpoint associated with the plugin's settings (e.g., a form targeting the plugin's options-saving action).
3. Social engineering: Deliver the malicious page to a logged-in WordPress administrator via phishing email, malicious link, or embedded iframe on a compromised site.
4. Trigger CSRF: When the authenticated administrator visits or loads the crafted page, their browser automatically submits the forged request with their session credentials, causing the plugin's settings to be modified without their knowledge (Patchstack).

• Logs: WordPress access logs showing unexpected POST requests to plugin-related admin-ajax.php or options.php endpoints from unusual referrer origins or with no referrer header.
• File System: Unexpected changes to plugin configuration or custom style definitions stored in the WordPress database (wp_options table) without corresponding administrator activity.
• Network: HTTP requests to WordPress admin endpoints originating from external or unexpected domains, particularly with auto-submitted form data patterns.

As of the disclosure date, no official patch has been released by the plugin developer for Just TinyMCE Custom Styles. Site administrators are advised to deactivate and remove the plugin until a patched version is available. As a general WordPress hardening measure, administrators should avoid clicking unsolicited links while logged into the WordPress dashboard, and consider using a Web Application Firewall (WAF) with CSRF protection rules. Patchstack users may benefit from virtual patching capabilities that can mitigate the vulnerability without requiring a plugin update (Patchstack).