| Plugin Name | Add infos to the events calendar |
|---|---|
| Type of Vulnerability | Cross-Site Scripting (XSS) |
| CVE Number | CVE-2024-11875 |
| Urgency | Low |
| CVE Publish Date | 2026-02-03 |
| Source URL | CVE-2024-11875 |
Urgent Security Advisory: CVE-2024-11875 — Stored XSS Vulnerability in ‘Add infos to the events calendar’ WordPress Plugin (≤1.4.1)
Published on 2026-02-03 by Managed-WP Security Experts
Executive Summary: A stored Cross-Site Scripting (XSS) vulnerability identified as CVE-2024-11875 affects the popular WordPress plugin “Add infos to the events calendar” in versions up to 1.4.1. Authenticated users with Contributor-level permissions can inject persistent malicious JavaScript code, which executes in the browsers of higher-privileged users or site guests. This exposure carries significant risks, including session hijacking and site compromise. This advisory details the vulnerability, security implications, detection methodologies, mitigation steps, and how Managed-WP provides advanced protections to safeguard your website.
Why This Vulnerability Demands Immediate Attention
Stored XSS is among the most critical classes of web security flaws because malicious scripts are permanently saved on a server and delivered to unsuspecting users. Attackers with Contributor access can exploit this by embedding harmful scripts into plugin-managed fields. When administrators or visitors load affected pages, these scripts execute, potentially leading to:
- Theft of authentication tokens and session cookies
- Privilege escalation through forged requests and CSRF
- Installation of persistent backdoors or malware
- Content defacement and redirection to malicious/phishing sites
- Damage to visitor trust and search engine rankings
Vulnerability Details:
CVE Identifier: CVE-2024-11875
Affected Plugin Versions: ≤ 1.4.1
Patch Available in Version: 1.5.0
Minimum Privilege Required: Contributor
Site owners using this plugin, especially those permitting Contributor-generated content, should prioritize remediation and protective measures without delay.
Technical Breakdown of the Vulnerability
The vulnerability arises as the plugin accepts user input from Contributor-level users, storing it without adequate sanitization or output escaping. As a result, malicious JavaScript embedded into event information is rendered unfiltered within event listings or administrative pages, triggering execution in browsers of Editors, Administrators, or other visitors.
Root Causes Include:
- Lack of server-side input sanitization when saving user-submitted content
- Failure to properly escape or sanitize output during page rendering
- Use of unsafe output methods that allow script execution (e.g., innerHTML, unescaped echo)
- Improperly enforced user role capabilities that allow unsafe content editing
This scenario requires an attacker to possess Contributor credentials or a compromised Contributor account to execute the attack chain.
Immediate Response: Critical Remediation Steps (Next 1–2 Hours)
- Verify plugin version and update immediately
Navigate to Plugins → Installed Plugins in WordPress Admin. If your version of “Add infos to the events calendar” is 1.4.1 or earlier, apply the 1.5.0 update without delay. This is the primary defense. - If update rollout is delayed, temporarily disable the plugin
Deactivate the plugin until testing and validation can be performed on the updated version. - Restrict or revoke Contributor content editing capabilities temporarily
Use role management plugins or custom code snippets to revoke privileges that allow contributors to add or edit event information. For example, consider removing ‘edit_posts’ capability:
// Temporarily remove edit_posts from contributors
$role = get_role('contributor');
if ( $role ) {
$role->remove_cap('edit_posts');
}
- Enhance Admin and Editor access controls
Limit backend access to trusted environments and advise key users to avoid clicking on untrusted links until the incident is resolved. - Audit recent user activity for suspicious content
Review event entries and plugin-related data created by Contributors within the last two weeks using activity logs or direct database queries. - Enable WAF rules to block malicious script injections
If your environment includes a Web Application Firewall like Managed-WP’s, enable or verify rules blocking script tags and suspicious payload patterns targeting the plugin inputs. - Force password resets and review accounts
Reset credentials for all contributors and administrative users, and rotate secret keys, API tokens, and application passwords as precaution. - Create full backups before remediation
Save complete site and database backups securely to enable rollback if needed during incident handling.
Detection Techniques: Verify if Your Site Has Been Targeted
Use the following investigative commands and queries to identify suspicious stored script injections:
- Database Search for Script Tags in Post Content:
SELECT ID, post_title, post_type, post_author
FROM wp_posts
WHERE post_content LIKE '%<script%';
- Check Plugin Meta Fields for Scripts:
SELECT meta_id, post_id, meta_key, meta_value
FROM wp_postmeta
WHERE meta_value LIKE '%<script%';
- List Recent Posts or Events From Contributors (using WP-CLI):
wp post list --post_type=event --format=csv --post_status=publish --author=$(wp user list --role=contributor --field=ID | tr '
' ',' ) --date_query='after=14 days ago'
- Search for Script Tags in Uploads or Plugin Data Using Grep:
grep -R --line-number "<script" wp-content/uploads/wp-event-infos/
- Review Browser Console Errors or Unexpected Script Output in Admin Event Pages
- Analyze Web Server Logs for Unusual POST Requests Targeting Plugin URLs
- Run Full Malware Scans Using Reliable Security Plugins or Managed-WP Scanner
Note: Preserve suspicious data snippets for forensic review before cleaning them.
Containment and Remediation of Confirmed Infections
- Isolate your website environment
Temporarily restrict external access or enable maintenance mode if active exploitation is suspected. - Export suspicious database records for investigation
Extract and archive affected rows containing injected scripts for analysis. - Sanitize or erase malicious scripts from stored content
Remove script tags or suspicious attributes using server-side sanitization functions such aswp_kses().
$clean = wp_kses( $raw_content, array(
'a' => array(
'href' => true,
'title' => true,
'rel' => true,
),
'strong' => array(),
'em' => array(),
'p' => array(),
'br' => array(),
'ul' => array(),
'ol' => array(),
'li' => array(),
) );
- Reset user credentials and keys
Enforce new passwords on affected accounts and rotate keys to disrupt sessions and API access. - Scan file system and scheduled tasks for anomalies
Check for unauthorized PHP files or Cron jobs that attackers may have planted. - Update the plugin to version 1.5.0 and validate fixes
Ensure the patched version is properly deployed and re-test for vulnerabilities. - Implement prolonged monitoring
Increase log retention and use WAF rules to detect and block similar attacks going forward. - Consider restoring from a clean backup if remediation is challenging
Long-Term Security Hardening Recommendations
Site integrity depends on both proactive and reactive controls. Manage your site security with these best practices:
- Limit Contributor permissions strictly and require manual content review before publishing
- Enforce Multi-Factor Authentication (MFA) for all Editor/Admin accounts
- Enable automatic and tested updates for plugins when feasible
- Deploy and maintain a Web Application Firewall (WAF) with virtual patching capabilities
- Maintain an incident response plan and regular offsite backups
- Harden core configuration, e.g., disable file edits in wp-config.php
define('DISALLOW_FILE_EDIT', true);
Plugin developers should adopt strict coding standards to prevent such flaws, including thorough input validation, output encoding, and robust capability checks.
Leveraging a WAF to Mitigate This Vulnerability
A capable WAF offers a critical security layer to block malicious attempts targeting known vulnerabilities while patches are deployed:
- Virtual patching to intercept attack patterns before they hit your codebase
- Rate limiting to deter brute force or mass injection attacks
- Input filters removing or escaping dangerous payloads (e.g., <script> tags)
- Behavioral detection to block suspicious contributor actions
Example WAF rule concept (illustrative only):
SecRule REQUEST_METHOD "POST" "phase:2,chain,deny,id:900100,msg:'Block script injection in event fields'"
SecRule ARGS_NAMES|ARGS "@rx (event_info|event_description|info_field)" "chain"
SecRule ARGS|REQUEST_BODY "@rx <script|onerror=|javascript:" "t:none,log,deny"
Important: Always rigorously test WAF rules in a staging environment to avoid disrupting legitimate site functionality.
Managed-WP customers benefit from continuously updated managed WAF rules and automated virtual patching that reduce risk exposure and accelerate incident response.
Recommended Logging and Monitoring Practices
- Enable WordPress debug logging (WP_DEBUG_LOG) securely
- Preserve and analyze server access logs, especially POST requests to plugin endpoints
- Retain logs for at least 90 days to facilitate thorough investigations
- Utilize centralized logging systems or SIEM tools to identify anomalies and repeated attack attempts
Look out for:
- Unusual bursts of plugin-related POST requests
- Multiple content edits from single accounts within short periods
- Signs of suspicious scripts or payloads in access logs
Threat Actor Scenarios: How Stored XSS Could Be Exploited
Attackers could leverage this flaw for:
- Account takeovers by stealing session cookies or forcing unauthorized actions
- Persistent website defacement or redirection to phishing sites
- Mass infections through injecting malware delivery scripts on public event pages
- Supply chain attacks impacting analytics, ad networks, or third-party integrations
This underscores the critical importance of rapid mitigation to prevent privilege escalation from contributor-level footholds.
Developer Guidance: Secure Coding Practices for Plugin Authors
To eliminate risks like CVE-2024-11875, developers should adhere to secure principles, including:
1. Sanitize inputs on save:
if ( isset( $_POST['event_info'] ) ) {
$allowed = array(
'a' => array( 'href' => true, 'title' => true, 'rel' => true ),
'p' => array(),
'br' => array(),
'strong' => array(),
'em' => array(),
'ul' => array(),
'ol' => array(),
'li' => array()
);
$sanitized = wp_kses( wp_kses_post( wp_strip_all_tags( $_POST['event_info'], true ) ), $allowed );
update_post_meta( $post_id, 'event_info', $sanitized );
}
2. Escape output properly:
$value = get_post_meta( $post_id, 'event_info', true );
echo wp_kses_post( $value ); // Safe rendering with HTML tags allowed
3. Check capabilities and validate nonces on admin requests:
if ( ! current_user_can( 'edit_post', $post_id ) ) {
wp_die( 'Permission denied' );
}
check_admin_referer( 'save_event_info_nonce' );
Following these standards will substantially reduce the risk of stored XSS in WordPress plugins.
Post-Incident Audit Checklist
- Confirm all environments run plugin version 1.5.0 or higher
- Review vendor changelogs and verify fixed vulnerabilities
- Check databases for residual malicious code
- Ensure output escaping is consistently applied
- Conduct automated and manual security audits of plugin code
Incident Response Summary
- Back up files and databases immediately (keep offsite copies)
- Patch or deactivate vulnerable plugins
- Scan and clean database content for malicious scripts
- Reset user credentials and rotate keys
- Review user accounts and revoke suspicious access
- Monitor logs intensively for 30+ days
- Engage professional forensic experts if compromise is confirmed
How Managed-WP Secures Your Site From Vulnerabilities Like CVE-2024-11875
Managed-WP equips your WordPress site with comprehensive, expert-level security solutions:
- Managed Web Application Firewall (WAF): deploys real-time, granular rules to block known exploits and suspicious payloads.
- Malware Scanning: continuously scans for malicious injections in posts, metadata, and uploaded files.
- Free Basic Plan: includes essential protections covering OWASP Top 10 vulnerabilities, offering immediate baseline security.
- Standard & Pro Plans: enhance defenses with auto-remediation, vulnerability virtual patching, monthly security reports, and priority support.
Pro plan users receive automatic virtual patch deployments to safeguard vulnerable endpoints while you schedule and validate plugin upgrades.
Quick Protection Tip: Get Started With Managed-WP’s Free Basic Plan
Take Control of Your Security Today
For rapid, hands-on protection during vulnerability triage, enroll in Managed-WP’s Free plan. It provides a managed firewall, robust WAF, malware scanning, and coverage of critical risk vectors — helping reduce immediate exposure as you remediate.
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Frequently Asked Questions
Q: Do site owners need to create their own WAF rules?
A: No. Managed firewall services like Managed-WP handle rule creation and updates. If managing your own WAF, use conservative rules and thoroughly test to avoid blocking legitimate users.
Q: Is this vulnerability limited to administrator users?
A: No. The stored XSS payload executes when any user or visitor loads the affected content, potentially compromising all site visitors depending on context.
Q: What if I have contributor users but do not use this plugin?
A: This specific advisory targets the named plugin, but best practice is to audit all plugins accepting user-generated HTML, apply least privilege principles, and maintain WAF protections site-wide.
Q: How urgent is the update?
A: Immediately. If immediate update is not feasible, apply mitigations such as plugin deactivation, capability restrictions, and WAF rule deployment, and plan urgent patching.
Final Thoughts From the Managed-WP Security Team
Securing WordPress sites requires swift patching, tight access controls, and layered defenses like WAFs and monitoring. Stored XSS vulnerabilities like CVE-2024-11875 highlight how attackers can escalate low-level user actions into full site compromises. Prioritize plugin updates, apply real-time protections, and keep vigilant monitoring.
If you need expert assistance with vulnerability triage or cleanup, Managed-WP offers scalable incident response and remediation services. Start with our free protection and scale up as needed for automated patching and priority support.
Stay secure. Follow plugin updates diligently and engage security professionals when in doubt.
— Managed-WP Security Team
References and Further Reading
- CVE-2024-11875 Official Entry
- WordPress Developer Handbook: Data Validation, Sanitization & Escaping
- OWASP XSS Prevention Cheat Sheet
(This technical advisory is independently produced based on public vulnerability disclosures. Plugin developers or site owners wishing to collaborate or request support may contact us at [email protected].)
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