What happened: short description

On 13 February 2026 a vulnerability (CVE-2025-14608) was disclosed in the WordPress plugin “WP Last Modified Info” that affects versions up to and including 1.9.5. The issue is an Insecure Direct Object Reference (IDOR) — a Broken Access Control condition — that allows authenticated users with the Author role to modify metadata on posts they do not own. The vendor released version 1.9.6 to address the problem.

Why this matters (threat models and attack scenarios)

At first glance changing “last modified” timestamps may seem cosmetic. In practice, uncontrolled post metadata modification can be used for:

• Ingeniería social: alter published or last-updated timestamps to convey false urgency or freshness.
• Reputation attacks: tamper with metadata that affects display or indexing, undermining visitor trust.
• SEO manipulation: if themes/plugins or external systems consume meta fields, inaccurate metadata can affect indexing or structured data.
• Lateral privilege abuse: a missing authorization check in one place often indicates similar gaps elsewhere; Authors able to modify postmeta may enable escalation when combined with other weaknesses.
• Supply-chain and editorial integrity risks: multi-author or membership sites rely on correct ownership assumptions; this breaks them.

The required privilege level is Author (not unauthenticated). That limits mass exploitation but still presents a meaningful risk on sites with multiple contributors, public signups, or delegated editorial roles.

Technical root cause (what developers got wrong)

IDOR occurs when an application accepts an object identifier (post ID, user ID, attachment ID, etc.) and performs actions on that object without verifying the acting user’s permission.

Likely implementation flaws in the vulnerable plugin include:

• Missing capability checks: using update_post_meta() or similar without calling current_user_can(‘edit_post’, $post_id) or current_user_can(‘edit_others_posts’).
• Insufficient nonce validation: AJAX or form handlers lacked valid nonces or depended on authentication alone rather than intent verification.
• Overly permissive endpoints: endpoints (admin-ajax.php, admin-post.php, or REST endpoints) accepting post IDs via GET/POST and performing updates without access control.
• Trusting client-supplied identifiers without cross-checking ownership or capabilities.

Secure patterns that should be enforced:

• Verify action nonces to confirm intent.
• Use current_user_can(‘edit_post’, $post_id) or explicit author checks where appropriate.
• Sanitize and validate every incoming identifier; restrict modifiable meta keys.

How an attacker might exploit it (high-level)

1. Attacker obtains or creates an account with Author privileges.
2. Identify the vulnerable request endpoint (an AJAX call or admin form) that accepts a post_id and metadata payload.
3. Craft a request to update postmeta for a post they do not own (e.g., change ‘last_modified’ or other metadata).
4. Because ownership/capability checks are missing, the request succeeds and metadata is changed.
5. Attacker uses altered metadata for misinformation, hiding changes, or as part of a larger attack chain.

Note: exploitation requires authentication at Author level. On sites where Authors are easily obtained, the attack surface increases.

Immediate detection steps for site owners

If you run WordPress and have the plugin installed, take these actions now.

1. Inventory your plugin version

Dashboard: Plugins → Installed Plugins → WP Last Modified Info.

WP-CLI:

wp plugin get wp-last-modified-info --field=version

2. Look for unexpected postmeta changes (quick SQL examples)

Identify likely meta keys used by the plugin and search:

SELECT post_id, meta_key, meta_value
FROM wp_postmeta
WHERE meta_key LIKE '%modified%' OR meta_key LIKE '%last%';

To narrow results to recent changes:

SELECT *
FROM wp_postmeta
WHERE meta_key IN ('_your_plugin_meta_key_here','wp_last_modified','last_modified')
  AND (meta_value LIKE '%2026-%' OR meta_value LIKE '%2025-%')
ORDER BY meta_id DESC
LIMIT 100;

3. Audit user activity

• Look for unusual Author activity (unexpected edits or meta changes at odd hours).
• List Authors via WP-CLI:

wp user list --role=author --fields=ID,user_login,user_email

4. Webserver and access logs

Search logs for POST requests to admin-ajax.php, admin-post.php or plugin-specific endpoints containing “post_id” or meta-related parameters.

grep -i "admin-ajax.php" /var/log/nginx/access.log | grep "post_id"

5. Restore points and backups

Check whether postmeta values differ between backups and the live database. If you find malicious changes, consider restoration of affected entries from recent backups.

Mitigation and remediation (short-term and long-term)

Immediate steps (if you cannot update the plugin right now)

• Desactiva el plugin if the functionality is not essential.
• Restrict role assignments: prevent new accounts from receiving Author role and review existing Authors.
• Controles de acceso temporales: remove untrusted Author accounts or demote them to Contributor until you can update.
• Apply virtual patching via your WAF: block requests that match exploitation patterns (see WAF examples below).
• Monitor and rollback: compare postmeta to backups and roll back malicious modifications.

Definitive fix

Update the plugin to the fixed version (1.9.6 or later). Verify the update enforces capability checks (current_user_can), nonce validation, and sanitised input handling.

Recommended secure code pattern (for developers)

Developers should use capability checks, nonce verification and input sanitisation when handling requests that include object IDs. Example handler pattern:

// Example secure handler
if ( ! isset( $_POST['wp_last_modified_nonce'] ) ||
     ! wp_verify_nonce( $_POST['wp_last_modified_nonce'], 'wp_last_modified_action' ) ) {
    wp_send_json_error( 'Invalid request' );
    exit;
}

$post_id = isset( $_POST['post_id'] ) ? intval( $_POST['post_id'] ) : 0;
if ( $post_id <= 0 ) {
    wp_send_json_error( 'Bad post ID' );
    exit;
}

// Capability check: does current user have edit rights for this post?
if ( ! current_user_can( 'edit_post', $post_id ) ) {
    wp_send_json_error( 'Unauthorized' );
    exit;
}

// Sanitize input before saving
$meta_key = sanitize_text_field( $_POST['meta_key'] );
$meta_value = sanitize_text_field( $_POST['meta_value'] );

// Restrict which meta keys can be modified via this endpoint
$allowed_meta_keys = array( 'last_modified_display', 'last_editor' );
if ( ! in_array( $meta_key, $allowed_meta_keys, true ) ) {
    wp_send_json_error( 'Meta key not allowed' );
    exit;
}

// Update safely
update_post_meta( $post_id, $meta_key, $meta_value );
wp_send_json_success( 'Updated' );

Parches virtuales y reglas de WAF (ejemplos)

If you cannot update immediately, a Web Application Firewall (WAF) can reduce risk by blocking likely exploit attempts. Below are general strategies and example rules. Always test rules in logging-only mode on staging before enabling blocking in production.

High-level WAF strategies

• Block or challenge POST requests to endpoints where the plugin processes metadata unless the session belongs to an Editor or Administrator.
• Intercept requests containing parameters such as post_id, meta_key or last_modified originating from Author-level sessions and require additional verification.
• Rate-limit sensitive endpoints and require stronger verification for bulk edits.

Ejemplo de regla estilo ModSecurity (conceptual)

# Block suspicious requests: POSTs to admin-ajax.php containing post_id + last_modified payload
SecRule REQUEST_METHOD "POST" "chain,phase:2,deny,status:403,id:1001001,msg:'Block potential IDOR: author modifying post meta',tag:'WP-IDOR'"
  SecRule REQUEST_URI "@contains admin-ajax.php" "chain"
  SecRule ARGS_NAMES|ARGS "@rx (post_id|meta_key|last_modified|last_modified_display)" "t:none"

More targeted rule (if plugin action param is known)

# If plugin uses action=wp_last_modified_update
SecRule REQUEST_METHOD "POST" "chain,phase:2,deny,status:403,id:1001002,msg:'Block WP Last Modified Info unprivileged postmeta changes'"
  SecRule ARGS:action "@streq wp_last_modified_update" "chain"
  SecRule ARGS:post_id "@rx ^\d+$" "t:none"

Generic rule recommendations

• Log-only first: configure rules to log matches and review for false positives.
• Block for confirmed exploit patterns: if a rule reliably identifies abusive requests, transition it to blocking mode.
• Consider CAPTCHAs or additional authentication steps for sensitive endpoints in editorial workflows.

Hardening your WordPress to reduce IDOR risk

1. Principio de Mínimos Privilegios — assign roles carefully; avoid granting Author to untrusted users. Use a Contributor role with editorial approval where possible.
2. Secure plugin development — enforce current_user_can checks, nonces and input validation for any endpoint accepting object IDs.
3. Staging and controlled updates — test updates in staging before production; maintain a plugin inventory.
4. Monitoreo y registro — enable activity logs and alert on anomalous Author behaviour (mass edits, cross-post metadata changes).
5. Limit attack surface — disable or restrict admin-ajax endpoints and unnecessary REST routes; only expose what is needed.
6. Regular scanning — schedule scans for unexpected metadata or file changes and review plugin maintenance activity.

Incident response checklist if you were exploited

1. Isolate activity — change administrative passwords and force user session resets; temporarily disable the vulnerable plugin if update is not possible.
2. Preservar evidencia — take a full backup (files + DB) before remediation and export relevant logs for forensic review.
3. Identify affected content — query wp_postmeta for suspicious meta changes and correlate with user activity logs.
4. Revert malicious changes — restore affected postmeta from backups or correct values manually after validation.
5. Apply fixes — update the plugin to 1.9.6+, apply WAF rules, and harden roles.
6. Scan for follow-up indicators — run malware scans and inspect uploads, themes and other plugins for suspicious files.
7. Acciones posteriores al incidente — rotate credentials, inform stakeholders if content was materially altered, and update your runbook.

Practical examples — Queries and commands

Examples for investigation and triage:

List recent postmeta changes via WP-CLI

wp db query "SELECT post_id, meta_key, meta_value, FROM_UNIXTIME(meta_id) AS change_time FROM wp_postmeta WHERE meta_key LIKE '%last%' ORDER BY meta_id DESC LIMIT 200;"

Find sudden changes across many posts

SELECT post_id, COUNT(*) as changes
FROM wp_postmeta
WHERE meta_key IN ('last_modified_display','last_modified_ts')
GROUP BY post_id
HAVING COUNT(*) > 3
ORDER BY changes DESC;

Review access logs for suspicious AJAX calls

awk '{print $1, $4, $7, $9, $12}' /var/log/nginx/access.log | grep "admin-ajax.php" | grep "post_id"

Testing WAF rules safely

• Start in logging-only mode and review matches for false positives.
• Observe traffic for a short window before switching to blocking mode.
• Test on a staging site that mirrors production traffic patterns where possible.

Por qué el parcheo virtual es útil

Virtual patching reduces exposure quickly while waiting for plugin updates. It is especially useful for:

• Large deployments that require coordination for testing and updates.
• Managed hosting setups where scheduled updates must be coordinated.
• Emergency situations where vendor response is delayed or a plugin is no longer maintained.

Use virtual patching as a stop-gap measure and still prioritise applying the definitive update as soon as practical.

Long-term recommendations for site owners and developers

• Treat the Author role as higher-risk; prefer a Contributor → Editor approval workflow where feasible.
• Adopt change control for plugins and test updates in staging.
• Enforce capability checks and nonces in all AJAX and REST endpoints that accept object IDs.
• Automate scanning and host-based detection for unexpected metadata or content changes.

Resumen y recomendaciones finales

• If you run "WP Last Modified Info" and your version is ≤ 1.9.5, update to 1.9.6 immediately — this is the definitive fix.
• If you cannot update right away: deactivate the plugin, restrict Author assignments, deploy WAF rules, and audit postmeta and logs for misuse.
• Restore from backup where necessary and scan for follow-up indicators after remediation.
• Adopt least-privilege practices and secure coding patterns to prevent IDOR and similar access-control flaws.

Appendix: Useful remediation checklist (copy/paste)

• [ ] Inventory plugin versions: Is WP Last Modified Info installed? Version ≤ 1.9.5?
• [ ] If yes, update to 1.9.6 (or deactivate temporarily)
• [ ] Search postmeta for suspicious changes and restore from backup if needed
• [ ] Review user roles; remove Author role from untrusted accounts
• [ ] Deploy WAF rules in log-only mode, review, then block
• [ ] Rotate admin credentials and review active sessions
• [ ] Scan site for other vulnerabilities and backdoors
• [ ] Re-run site tests and monitor logs for repeated exploit attempts