CVE-2026-56057 Overview
CVE-2026-56057 is a PHP Object Injection vulnerability affecting the Uncanny Automator Pro WordPress plugin in versions up to and including 7.3.0.6. The flaw allows authenticated users with subscriber-level access to inject serialized PHP objects into the application. When these objects are deserialized, attackers can trigger unintended code paths through PHP magic methods, potentially leading to remote code execution, arbitrary file operations, or data compromise. The vulnerability is tracked under CWE-502: Deserialization of Untrusted Data.
Critical Impact
Authenticated subscribers can inject PHP objects to compromise site confidentiality, integrity, and availability across affected WordPress installations.
Affected Products
- Uncanny Automator Pro plugin for WordPress
- Versions <= 7.3.0.6
- WordPress installations with subscriber-level registration enabled
Discovery Timeline
- 2026-06-26 - CVE-2026-56057 published to NVD
- 2026-06-26 - Last updated in NVD database
Technical Details for CVE-2026-56057
Vulnerability Analysis
The vulnerability stems from unsafe deserialization of user-supplied input within the Uncanny Automator Pro plugin. PHP's unserialize() function reconstructs objects from string input and invokes magic methods such as __wakeup(), __destruct(), and __toString() during the process. When attacker-controlled data reaches this function, the resulting object graph can be crafted to trigger property-oriented programming (POP) chains within loaded classes.
The attack requires only subscriber privileges, which represent the lowest authenticated role in WordPress. Many sites allow open subscriber registration, effectively lowering the bar to near-unauthenticated access. Once an object is deserialized, an attacker can leverage gadget chains present in the plugin, WordPress core, or other installed plugins to achieve code execution, arbitrary file writes, or SQL injection.
Root Cause
The plugin passes untrusted input to a deserialization routine without validating or restricting the accepted class types. PHP object injection vulnerabilities [CWE-502] arise when serialized data crosses a trust boundary and is reconstructed without integrity checks such as HMAC verification or safe alternatives like json_decode().
Attack Vector
An authenticated subscriber sends a crafted request to a vulnerable plugin endpoint containing a serialized PHP payload. The plugin deserializes the payload, instantiating attacker-chosen classes with attacker-controlled properties. Chained magic methods then execute existing code in unintended ways, producing side effects such as writing to the filesystem or invoking database queries. Refer to the Patchstack WordPress Vulnerability Report for advisory details.
Detection Methods for CVE-2026-56057
Indicators of Compromise
- HTTP requests containing serialized PHP patterns such as O: followed by class name length and name (for example, O:8:"stdClass") in POST bodies or query parameters targeting Uncanny Automator endpoints.
- Unexpected file creation or modification in the WordPress wp-content/uploads or plugin directories following subscriber activity.
- New or modified WordPress user accounts with elevated roles created shortly after subscriber authentication events.
- PHP error log entries referencing __wakeup, __destruct, or unserialization failures tied to plugin request handlers.
Detection Strategies
- Inspect web server access logs for requests from subscriber accounts containing serialized object signatures like a:, O:, or s: in parameter values.
- Correlate WordPress audit logs with outbound network connections from the PHP worker process to identify post-exploitation callbacks.
- Deploy web application firewall rules that flag serialized PHP payloads submitted to authenticated plugin endpoints.
Monitoring Recommendations
- Enable file integrity monitoring across the WordPress installation, including plugin and theme directories.
- Alert on privilege changes, new administrator accounts, or unexpected role escalations tied to subscriber sessions.
- Monitor PHP process behavior for anomalous child processes, outbound connections, or shell invocations originating from the web server user.
How to Mitigate CVE-2026-56057
Immediate Actions Required
- Update Uncanny Automator Pro to a version later than 7.3.0.6 as soon as the vendor releases a patched build.
- Audit all subscriber accounts and disable open registration if it is not required for business operations.
- Review WordPress user roles and remove accounts created during the exposure window that show suspicious activity.
Patch Information
Consult the Patchstack WordPress Vulnerability Report for the latest fixed version and vendor guidance. Apply updates through the WordPress plugin dashboard or via WP-CLI once the patched release is available.
Workarounds
- Temporarily deactivate the Uncanny Automator Pro plugin until a patched version is installed.
- Restrict subscriber registration by setting Anyone can register to disabled under WordPress General Settings.
- Deploy a web application firewall rule to block serialized PHP payloads in requests to plugin endpoints.
- Enforce strong role separation and remove unused authenticated accounts to reduce the attack surface.
# Disable open registration and update the plugin via WP-CLI
wp option update users_can_register 0
wp plugin update uncanny-automator-pro
wp user list --role=subscriber --fields=ID,user_login,user_registered
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
