CVE-2025-53243: WordPress Employee Directory Plugin Flaw

CVE-2025-53243 Overview

CVE-2025-53243 is a PHP Object Injection vulnerability in the emarket-design Employee Directory – Staff Listing & Team Directory Plugin for WordPress. The flaw stems from deserialization of untrusted data [CWE-502] and affects all plugin versions up to and including 4.5.5. An unauthenticated attacker can submit crafted serialized payloads to trigger object instantiation within the plugin's PHP context. When combined with a suitable property-oriented programming (POP) chain from WordPress core or other installed plugins, exploitation can lead to arbitrary code execution, file operations, or full site compromise.

Critical Impact
Unauthenticated PHP Object Injection enabling potential remote code execution, data tampering, and full WordPress site compromise on installations running plugin versions through 4.5.5.

Affected Products

Employee Directory – Staff Listing & Team Directory Plugin for WordPress (emarket-design) versions through 4.5.5
WordPress installations with the vulnerable plugin enabled
Sites bundling additional plugins or themes that expose usable POP gadget chains

Discovery Timeline

2025-08-28 - CVE-2025-53243 published to NVD
2026-04-28 - Last updated in NVD database

Technical Details for CVE-2025-53243

Vulnerability Analysis

The plugin invokes PHP's unserialize() function on attacker-controlled input without prior validation or integrity checks. PHP deserialization reconstructs arbitrary objects and automatically triggers magic methods such as __wakeup(), __destruct(), and __toString() on those objects. When a vulnerable class with side-effect-bearing magic methods exists in the runtime, attackers can chain method invocations to read or write files, execute shell commands, or alter database records.

WordPress environments are especially exposed because the global class space includes core classes, theme classes, and every active plugin's classes. A single object injection sink — like the one in this plugin — provides the entry point that turns a benign-looking gadget chain into remote code execution.

The high attack complexity reflected in the CVSS vector indicates the attacker must identify or supply a working POP chain. Public gadget chains for common WordPress dependencies (Monolog, Guzzle, phpggc-published chains) substantially lower that barrier.

Root Cause

The plugin deserializes user-supplied input — likely from HTTP request parameters, cookies, or stored metadata — using PHP's native unserialize() rather than safe formats such as JSON. No allowlist of permitted classes is enforced via the allowed_classes option.

Attack Vector

The vulnerability is exploitable over the network without authentication and without user interaction. An attacker crafts a serialized PHP object string referencing a gadget chain, then submits it through a request handler that the plugin processes with unserialize(). Successful deserialization triggers the gadget chain and produces the attacker's intended side effects under the WordPress process identity.

Refer to the Patchstack WordPress Vulnerability Report for advisory details.

Detection Methods for CVE-2025-53243

Indicators of Compromise

HTTP request bodies, query strings, or cookies containing PHP serialization markers such as O:, a:, or s: followed by length-prefixed class names
Unexpected outbound connections, new PHP files in wp-content/, or modified .htaccess entries following plugin requests
New or modified WordPress administrator accounts and unexpected scheduled tasks in wp_options (cron)
Webshell artifacts dropped into the plugin or uploads directory

Detection Strategies

Inspect web server access logs for requests to plugin endpoints containing serialized object patterns matching the regex O:\d+:"
Monitor PHP error logs for unserialize() warnings, undefined class notices, or fatal errors during magic method execution
Compare plugin file hashes against a known-good 4.5.5 baseline to detect tampering
Correlate WordPress request telemetry with file system change events and outbound network connections from the PHP worker process

Monitoring Recommendations

Enable WordPress audit logging for user, role, and option changes, and forward logs to a centralized analytics platform
Deploy a web application firewall with rules that block serialized PHP objects in untrusted input fields
Alert on creation of PHP files outside expected directories and on modifications to WordPress core or plugin files

How to Mitigate CVE-2025-53243

Immediate Actions Required

Update the Employee Directory – Staff Listing & Team Directory Plugin to a version later than 4.5.5 as soon as the vendor releases a fix
If no fixed version is available, deactivate and remove the plugin until a patch is published
Audit WordPress administrator accounts, scheduled tasks, and recently modified files for signs of post-exploitation activity
Rotate WordPress secrets in wp-config.php and reset administrator credentials if compromise is suspected

Patch Information

The Patchstack advisory identifies all versions through 4.5.5 as vulnerable. Site administrators should monitor the plugin page on WordPress.org and the Patchstack WordPress Vulnerability Report for the corrected release and apply it across all environments.

Workarounds

Use a virtual patching rule on the WAF to block requests containing PHP serialization signatures targeting plugin endpoints
Restrict access to the WordPress site to authenticated users or known IP ranges where feasible
Run PHP with restricted disable_functions settings to limit the impact of any successful gadget chain execution

bash

# Example ModSecurity rule to block PHP serialized objects in request bodies
SecRule REQUEST_URI "@contains /wp-content/plugins/employee-directory/" \
    "id:1005321,phase:2,deny,status:403,log,\
     msg:'Possible PHP Object Injection attempt (CVE-2025-53243)',\
     chain"
  SecRule REQUEST_BODY|ARGS|REQUEST_COOKIES "@rx O:\d+:\"[A-Za-z_\\\\][A-Za-z0-9_\\\\]*\":\d+:\{" \
      "t:none,t:urlDecodeUni"