CVE-2026-10749: Post Duplicator WordPress Plugin RCE Flaw

CVE-2026-10749 Overview

CVE-2026-10749 is a PHP Object Injection vulnerability in The Post Duplicator WordPress plugin before version 3.0.15. The plugin fails to safely handle custom meta-data during post duplication. It stores attacker-supplied serialized values without applying the WordPress meta API's double-serialization protection. Authenticated users with Contributor-level access or higher can inject arbitrary PHP objects through crafted meta values. Successful exploitation depends on the presence of a suitable POP (Property-Oriented Programming) gadget chain in the WordPress core, another plugin, or theme loaded on the site.

Critical Impact
Authenticated Contributors can inject PHP objects leading to potential remote code execution, data tampering, or full site compromise when a usable gadget chain is present.

Affected Products

The Post Duplicator WordPress plugin versions prior to 3.0.15
WordPress sites with Contributor-level (or higher) user registration enabled
Any deployment where vulnerable plugin is combined with plugins/themes exposing POP gadget chains

Discovery Timeline

2026-06-24 - CVE-2026-10749 published to NVD
2026-06-24 - Last updated in NVD database

Technical Details for CVE-2026-10749

Vulnerability Analysis

The vulnerability resides in the post duplication routine of The Post Duplicator plugin. When duplicating a post, the plugin copies custom meta-data from the source post to the new post. WordPress provides a meta API (add_post_meta, update_post_meta) that automatically applies a second serialization step to array and object values. This double-serialization prevents stored serialized payloads from being unserialized when read back. The Post Duplicator bypasses this protection by writing serialized values directly, allowing raw serialized data to persist in the database. When the meta value is later retrieved and processed by code that calls unserialize(), attacker-controlled PHP objects are instantiated. This is a classic [CWE-502] Insecure Deserialization issue.

Root Cause

The root cause is improper use of the WordPress metadata storage layer. The plugin stores meta values without routing them through the standard meta API, skipping the double-serialization safeguard. Serialized payloads supplied by a Contributor in source post meta-data are preserved verbatim and re-emitted as serialized strings on read.

Attack Vector

An authenticated user with Contributor permissions creates a post containing a crafted meta value holding a serialized PHP object payload. The attacker then triggers the duplication action exposed by the plugin. The duplicated post stores the serialized payload without protective re-serialization. Any subsequent code path that calls unserialize() on this meta value instantiates the attacker's object, triggering magic methods such as __wakeup or __destruct. Chained with a POP gadget present in WordPress core, another plugin, or theme, this can escalate to file write, SQL injection, or arbitrary code execution.

No verified public proof-of-concept code is available. For technical specifics, refer to the WPScan Vulnerability Report.

Detection Methods for CVE-2026-10749

Indicators of Compromise

Unexpected serialized strings beginning with O: or a: stored in the wp_postmeta table on duplicated posts
Creation of duplicate posts by Contributor-level accounts immediately following meta-data edits
PHP errors referencing unserialize(), __wakeup, or __destruct in web server logs
New or modified files in the WordPress webroot following plugin activity by low-privileged users

Detection Strategies

Audit installed plugin versions and flag any Post Duplicator installation below 3.0.15
Query wp_postmeta for meta_value entries matching PHP serialization patterns on posts owned by Contributor accounts
Monitor WordPress audit logs for the plugin's duplication action invoked by non-Administrator users
Correlate post duplication events with subsequent file-system or database changes

Monitoring Recommendations

Enable verbose PHP error logging and forward logs to a centralized SIEM for pattern matching
Alert on unusual outbound network connections originating from the PHP-FPM or web server process
Track creation of new administrative users or modifications to wp_options shortly after duplication events
Baseline normal Contributor activity and alert on deviations involving meta-data manipulation

How to Mitigate CVE-2026-10749

Immediate Actions Required

Update The Post Duplicator plugin to version 3.0.15 or later on every WordPress instance
Review Contributor and higher accounts and remove unused or untrusted users
Inspect existing duplicated posts for suspicious serialized meta-data and purge affected records
Audit installed plugins and themes for known POP gadget chains and update or remove vulnerable components

Patch Information

The vendor addressed the issue in The Post Duplicator version 3.0.15 by routing meta-data through the WordPress meta API so that serialized values receive the standard double-serialization protection. Refer to the WPScan Vulnerability Report for advisory details.

Workarounds

Deactivate The Post Duplicator plugin until the patched version can be deployed
Restrict the plugin's duplication capability to Administrator-level accounts via custom capability mapping
Disable open user registration or downgrade untrusted accounts below Contributor
Deploy a web application firewall rule blocking serialized PHP object patterns in post meta submissions

bash

# Update The Post Duplicator via WP-CLI to the fixed version
wp plugin update post-duplicator --version=3.0.15

# Verify installed version
wp plugin get post-duplicator --field=version

# Identify serialized object payloads in postmeta (review before removal)
wp db query "SELECT meta_id, post_id, meta_key FROM wp_postmeta WHERE meta_value LIKE 'O:%' OR meta_value LIKE 'a:%:{%O:%';"