Include Me Plugin (<=1.3.2) XSS: What WordPress Site Owners Must Do Right Now

By Hong Kong Security Expert — 2025-09-10

A Cross‑Site Scripting (XSS) vulnerability has been disclosed in the “Include Me” WordPress plugin (versions up to and including 1.3.2; fixed in 1.3.3, see CVE-2025-58983). This advisory explains the technical risk, realistic attack scenarios, who is affected, immediate containment steps, safe remediation, and longer‑term hardening measures. The guidance is practical and aimed at site owners and technical teams.

Executive summary (the tl;dr)

• Vulnerability: Stored Cross‑Site Scripting (XSS) in Include Me plugin ≤ 1.3.2 (CVE-2025-58983).
• Required privilege (reported): Administrator.
• Impact: Stored XSS enabling JavaScript/HTML injection that executes in visitors’ or administrators’ browsers.
• Severity: CVSS around 5.9 (medium), context-dependent; real risk grows if administrative credentials are compromised.
• Fixed in: 1.3.3 — update immediately if the plugin is in use.
• If you cannot update now: restrict admin access, deactivate the plugin if feasible, enforce monitoring and containment.

Why XSS still matters (even if it “only” needs an admin)

An XSS that requires an administrator to submit content may appear low risk, but in practice administrative accounts are common targets. Password reuse, phishing and prior breaches lead to elevated likelihood that an attacker can gain admin privileges. Stored XSS can be used to:

• Deliver phishing pages and steal credentials.
• Create additional admin accounts or modify content persistently.
• Install scripts that load backdoors or persistent connectors to remote infrastructure.
• Inject spam, malicious redirects, or SEO‑poisoning content that harms reputation.

Automated scanners will attempt exploitation quickly after disclosure — so even a seemingly minor exposure can escalate rapidly.

What the vulnerability can do (realistic attack scenarios)

Stored XSS can have many practical consequences; examples include:

• Session theft or token exfiltration (when combined with other weaknesses).
• Silent admin takeover flows: creating users, changing passwords, injecting persistent scripts or backdoors.
• Malvertising, drive‑by redirects, or fake update prompts to deliver malware to visitors.
• Phishing under the site’s own domain for higher credibility.
• Bypassing browser‑reliant controls (stealing CSRF tokens, altering client‑side logic).

Who is affected

• Any WordPress installation running Include Me ≤ 1.3.2 is potentially vulnerable.
• The reported required privilege is Administrator: an attacker with admin access can exploit this to broaden control.
• Sites with multiple operators or third‑party agencies that have admin access are higher risk.

Immediate actions (first 90 minutes)

1. Check plugin version
   • WP Admin → Plugins to view the installed version.
   • Or via command line: wp plugin get include-me --field=version.
2. If on ≤ 1.3.2: Update immediately

   Apply the plugin update to 1.3.3 (or later). If your environment permits, prioritise the security update even if you plan later testing in staging.

3. If you cannot update right away
   • Place the site behind maintenance mode where feasible.
   • Restrict wp-admin access by IP allowlist, VPN, or web‑server rules.
   • Temporarily deactivate the plugin if it is non‑essential.
   • Enable or enforce multi‑factor authentication for all admin accounts and rotate admin passwords.
4. Inspect admin‑editable content

   Search for recently modified content in plugin settings and pages managed by the plugin. Look for unexpected <script> tags, inline event handlers (onerror, onload) or suspicious iframes.

5. Review logs and scan

   Check web server access logs and WordPress audit logs for unusual admin activity or POSTs to plugin endpoints. Run a site malware scan and a file integrity check.

Safe remediation and recovery steps (if you suspect compromise)

1. Isolate and preserve evidence

   Take a snapshot of files and the database for forensic analysis. Preserve logs and do not overwrite evidence.

2. Replace compromised content

   Remove injected scripts from posts, plugin settings and any stored fields.

3. Reset credentials and secrets

   Reset admin passwords, API keys and any tokens stored in options. Invalidate external integration credentials if they may be compromised.

4. Search for web shells and unauthorized tasks

   Inspect wp-content/uploads, wp-content/plugins and wp-includes for unexpected files. Check wp_options for rogue autoloaded entries and wp_posts for suspicious content.

5. Restore from clean backup where needed

   If you cannot confidently remove all malicious artifacts, restore from a known clean backup created before the incident.

6. Rotate keys and certificates if required

   Generally rare, but rotate signing keys and reissue certificates if you have evidence of theft.

7. Reinforce hardening

   After cleanup, apply the long‑term controls listed below to reduce future risk.

Why updating is the best long‑term fix

Patching to the fixed release (1.3.3 or later) corrects the root cause in the plugin code. Temporary mitigations (such as firewall rules) can reduce risk between disclosure and patching, but they do not substitute for the upstream code fix.

How a web application firewall (WAF) or managed firewall can help now

While not a permanent substitute for patching, WAFs and similar protections can reduce exposure quickly:

• Virtual patching: block submissions containing script tags, event handlers or common XSS signatures aimed at plugin endpoints.
• Positive‑input enforcement: restrict admin POSTs that include raw HTML unless from trusted sources.
• Rate limiting and anomaly detection to hinder automated scanning and mass injection attempts.
• IP allowlisting for administrative interfaces and enhanced logging for attempted exploits.

Practical (safe) technical guidance for developers and site maintainers

Secure coding and operational controls that reduce XSS risk:

1. Escaping and sanitisation
   • Use context‑appropriate functions: esc_html(), esc_attr(), wp_kses(), esc_url().
   • For input: sanitize_text_field(), wp_kses_post() when limited HTML is required.
   • Prefer storing raw data only if you will perform correct escaping at render time; if HTML is allowed, use a strict whitelist via wp_kses().
2. Capability and nonce checks
   • Validate user capabilities before processing sensitive inputs (for example, current_user_can('manage_options')).
   • Use nonces on form submissions (check_admin_referer(), wp_verify_nonce()).
3. Least privilege

   Avoid granting admin privileges to accounts that do not need them; use granular roles.

4. Update behaviour and backups

   Implement controlled automatic updates where appropriate and ensure reliable backups with tested restores.

5. Logging and monitoring

   Record admin activity and set alerts for new admin accounts or bulk content changes.

6. Content Security Policy (CSP)

   Use a restrictive CSP to reduce the impact of injected scripts (avoid 'unsafe-inline'; prefer nonces or hashes for approved inline scripts).

7. Security headers and cookie flags

   Ensure session cookies have HttpOnly, Secure and appropriate SameSite flags. Use X-Frame-Options or frame‑ancestors to prevent clickjacking.

How to check whether you’re affected (step‑by‑step, safe checks)

1. Identify plugin version: WP Admin → Plugins or wp plugin get include-me --field=version.
2. Search for plugin data in the database (read‑only): look for options or posts containing the plugin prefix and inspect values for <script> tags or on* attributes.
3. Review recent admin edits via audit logs if available.
4. Inspect web server logs for POSTs to plugin endpoints and suspicious payloads.
5. Run a reputable malware or static scanner over code and database for indicators of XSS or injected content.

Note: avoid running destructive exploit checks on production. Use staging or read‑only inspections where possible.

If you operate a multi‑site environment or agency: additional considerations

• Audit all client sites and keep an inventory of installed plugins and versions.
• Prioritise critical security patches; roll out staged updates but act quickly for vulnerabilities with public disclosure.
• Use centralised management tools that support safe bulk updates and pre‑update backups.
• Communicate clearly with clients about required actions, potential downtime and remediation steps.

What secure plugin authors should have done (and what to look for in future releases)

• Validate and escape output consistently throughout the codebase.
• Restrict which fields accept HTML and document that clearly in the UI.
• Harden admin forms with capability checks and nonces.
• Provide clear changelogs for security fixes and a coordinated disclosure process.

Incident response checklist (concise)

• Update Include Me to 1.3.3 (or deactivate the plugin).
• Enforce MFA and rotate admin credentials.
• Backup site and database for forensics.
• Scan for malicious files and database changes; remove injected content.
• Revoke and reissue any exposed API keys.
• Monitor for suspicious outbound connections or scheduled tasks.
• If unsure about cleanup, engage a qualified incident response provider.

Hardening checklist after remediation

• Enforce strong passwords and MFA for all admin users.
• Limit admin‑level accounts; separate duties where possible.
• Keep WordPress core, themes and plugins updated.
• Use a WAF or other edge protections and consider virtual patching only as a temporary measure.
• Maintain a tested backup strategy and regular restores.
• Implement monitoring, alerting and periodic security scans.

Why you shouldn’t wait to act

Automated exploit scanners and bots begin probing exposed sites within hours of disclosure. Rapid updates and basic hardening drastically reduce attack surface and the likelihood of prolonged compromise. Treat this as routine hygiene: patch now to avoid costly recovery later.

Immediate mitigation options (if you cannot patch straight away)

• Restrict administrative access by IP or VPN.
• Temporarily deactivate the plugin if it is not essential.
• Enforce MFA and rotate all admin passwords.
• Place the site in maintenance mode to reduce visitor exposure.
• Apply server‑level rules to block suspicious POST payloads targeting the plugin.

Final thoughts from Hong Kong security experts

Include Me XSS is actionable and fixable: update to 1.3.3 and follow the containment and recovery steps above. The Hong Kong web security community sees similar patterns repeatedly — quick patching, least privilege, MFA and vigilant monitoring are high‑value controls that prevent small issues from becoming major incidents.

If you need a concise incident playbook tailored to your environment (site scale, hosting type and admin model), engage a qualified responder and provide your site profile so they can prepare a short operational plan you can execute within a few hours.