CVE-2025-23826 Overview
CVE-2025-23826 is a stored Cross-Site Scripting (XSS) vulnerability in the Stop Comment Spam WordPress plugin by pedjas. The flaw affects all versions up to and including 0.5.3. The vulnerability is chained from a Cross-Site Request Forgery (CSRF) weakness, enabling attackers to persist malicious JavaScript when an authenticated administrator is tricked into visiting an attacker-controlled page. The stored payload executes in the browser of any subsequent visitor, exposing site users and administrators to session theft and unauthorized actions. The issue is categorized under CWE-79 (Improper Neutralization of Input During Web Page Generation).
Critical Impact
Successful exploitation allows attackers to inject persistent JavaScript into the WordPress site, compromising visitor sessions and enabling administrative actions through hijacked accounts.
Affected Products
- pedjas Stop Comment Spam WordPress plugin
- All versions from n/a through 0.5.3
- WordPress installations with the stop-comment-spam plugin enabled
Discovery Timeline
- 2025-01-16 - CVE-2025-23826 published to NVD
- 2026-04-23 - Last updated in NVD database
Technical Details for CVE-2025-23826
Vulnerability Analysis
The vulnerability resides in the Stop Comment Spam plugin's settings handling logic. The plugin fails to properly neutralize user-supplied input before rendering it within web page output. This omission permits an attacker to inject arbitrary HTML and JavaScript that persists in the plugin's configuration and executes on page load.
The issue is compounded by missing CSRF protection on the plugin's settings update endpoint. An attacker hosts a malicious page that submits a forged request to the plugin's configuration handler. When an authenticated administrator visits the attacker page, the browser silently submits the request, storing the attacker's payload.
The EPSS score is 0.344% with a percentile of 57.09, indicating measurable but not widespread exploitation interest.
Root Cause
The plugin lacks two security controls. First, no CSRF nonce verification protects the settings update workflow, so the application cannot distinguish legitimate administrator submissions from forged cross-origin requests. Second, output encoding is missing when stored settings are echoed back into administrative or public pages, allowing raw <script> tags or event handlers to execute.
Attack Vector
The attack requires user interaction from a privileged WordPress user. The attacker crafts a web page containing an auto-submitting form targeting the plugin's settings endpoint. The form payload includes JavaScript embedded in a configurable plugin field. When an authenticated administrator visits the page, the request executes under their session, storing the payload. The malicious script then runs in the browser of every user who loads the affected page.
No verified public exploit code is available. See the Patchstack Vulnerability Report for technical details.
Detection Methods for CVE-2025-23826
Indicators of Compromise
- Unexpected <script> tags, onerror, or onload handlers present in WordPress plugin settings stored in the wp_options table.
- Outbound browser requests from administrator sessions to unfamiliar domains shortly after visiting external links.
- Modifications to stop-comment-spam plugin options without corresponding entries in WordPress admin audit logs.
Detection Strategies
- Inspect the wp_options table for rows associated with the stop-comment-spam plugin and search for HTML or JavaScript syntax in stored values.
- Deploy a web application firewall (WAF) rule that flags POST requests to plugin admin endpoints lacking a valid Referer or Origin header matching the site domain.
- Review web server access logs for requests to wp-admin/options-general.php or plugin-specific endpoints originating from external referrers.
Monitoring Recommendations
- Monitor administrator browser sessions for anomalous JavaScript execution and unexpected cross-origin requests.
- Alert on changes to active plugin configuration values, especially those containing angle brackets or javascript: URIs.
- Track outbound network connections from web server processes to identify exfiltration channels established through injected scripts.
How to Mitigate CVE-2025-23826
Immediate Actions Required
- Deactivate the Stop Comment Spam plugin on all WordPress instances running version 0.5.3 or earlier until a patched release is verified.
- Audit the plugin's stored options for injected payloads and remove any suspicious entries directly from the database.
- Force a password reset and session invalidation for all WordPress administrators who may have been exposed.
Patch Information
No fixed version is identified in the available advisory data. Refer to the Patchstack Vulnerability Report for current remediation guidance and replace the plugin with a maintained alternative if no patch is released.
Workarounds
- Remove the stop-comment-spam plugin entirely and rely on alternative anti-spam solutions with active maintenance.
- Restrict WordPress administrator access to dedicated browsers or sessions that do not visit untrusted external sites.
- Deploy a Content Security Policy (CSP) header that disallows inline scripts to limit the impact of stored XSS payloads.
# Example CSP header to mitigate inline script execution
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
