CVE-2025-54012: Welcart e-Commerce Object Injection Flaw

CVE-2025-54012 Overview

CVE-2025-54012 is a PHP Object Injection vulnerability in the Welcart e-Commerce usc-e-shop plugin for WordPress. The flaw stems from deserialization of untrusted data [CWE-502] and affects all plugin versions up to and including 2.11.16. An authenticated attacker with high privileges can pass crafted serialized payloads to a vulnerable unserialize() call, triggering object instantiation under attacker control.

When exploited alongside a present POP (Property-Oriented Programming) chain, the issue can lead to arbitrary code execution, file operations, or data tampering within the WordPress instance. The vulnerability requires no user interaction and is reachable over the network.

Critical Impact
Successful exploitation can result in full compromise of confidentiality, integrity, and availability of the affected WordPress site, with potential for remote code execution if a usable gadget chain is present.

Affected Products

Welcart e-Commerce (usc-e-shop) WordPress plugin versions through 2.11.16
WordPress sites running the vulnerable plugin with authenticated administrative access exposed
Hosting environments where PHP processes the plugin's deserialization endpoints

Discovery Timeline

2025-08-20 - CVE-2025-54012 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-54012

Vulnerability Analysis

The Welcart e-Commerce plugin processes serialized PHP data from a privileged input path without validating the structure or origin of that data. PHP's unserialize() function reconstructs objects directly from the input string. When attacker-controlled bytes reach this function, PHP invokes magic methods such as __wakeup, __destruct, and __toString on instantiated classes.

If any loaded class implements one of these methods with side effects, an attacker can chain calls to reach dangerous sinks. Typical sinks include file write primitives, SQL execution, or shell command invocation. The plugin operates within the WordPress runtime, so the entire class universe of WordPress core, themes, and other active plugins becomes available for gadget construction.

The issue is tracked as a Deserialization of Untrusted Data weakness and is categorized as Insecure Deserialization / Object Injection. Exploitation requires authenticated access with high privileges, which limits scope to insider threats or attackers who have already obtained admin credentials through phishing, credential stuffing, or chained vulnerabilities.

Root Cause

The root cause is direct invocation of unserialize() on input that crosses a trust boundary without prior validation, allow-listing, or use of safe alternatives such as json_decode(). The plugin does not apply the allowed_classes option introduced in PHP 7 to constrain which classes may be instantiated during deserialization.

Attack Vector

An authenticated administrator-level user submits a serialized PHP object string to a vulnerable plugin endpoint within the usc-e-shop plugin. The plugin deserializes the payload, triggering magic methods on classes available in the WordPress runtime. With a suitable gadget chain, the attacker pivots from object injection to arbitrary PHP execution or file system manipulation. Refer to the Patchstack Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-54012

Indicators of Compromise

HTTP POST requests to usc-e-shop plugin endpoints containing serialized PHP markers such as O:, a:, or s: followed by length-prefixed strings
New or modified PHP files under wp-content/uploads/ or plugin directories shortly after suspicious admin activity
Unexpected outbound connections from the web server process to attacker infrastructure
WordPress admin sessions originating from anomalous geographies or IP ranges

Detection Strategies

Inspect web server access logs for request bodies containing PHP serialization syntax targeting the Welcart plugin paths
Enable WordPress audit logging to capture administrative actions involving plugin configuration changes
Run static analysis on installed plugin code to identify unserialize() calls receiving request-derived data

Monitoring Recommendations

Forward web server, PHP-FPM, and WordPress audit logs to a centralized log analytics platform for correlation
Alert on PHP processes spawning shell commands, network connections, or writing executable files
Track plugin version inventory across WordPress fleets and flag instances of usc-e-shop at or below 2.11.16

How to Mitigate CVE-2025-54012

Immediate Actions Required

Upgrade the Welcart e-Commerce (usc-e-shop) plugin to a version released after 2.11.16 that addresses the deserialization flaw
Audit WordPress administrator accounts, rotate credentials, and enforce multi-factor authentication on all privileged users
Restrict access to the WordPress admin interface using IP allow-listing or VPN-only access where feasible
Review server file systems and databases for signs of post-exploitation activity following any suspicious admin sessions

Patch Information

Apply the vendor-provided update for the usc-e-shop plugin. Patch details and version guidance are available in the Patchstack Vulnerability Report. Validate the installed plugin version after upgrade by checking the WordPress plugins dashboard.

Workarounds

Deactivate the Welcart e-Commerce plugin until the patched version can be installed
Place a web application firewall rule in front of WordPress that blocks request bodies containing PHP serialization patterns directed at the plugin endpoints
Limit which user roles can reach plugin administrative actions through role and capability management

bash

# Example WAF rule fragment blocking serialized PHP payloads to Welcart endpoints
# Adjust to your WAF syntax
SecRule REQUEST_URI "@contains /wp-admin/admin.php" \
  "chain,phase:2,deny,status:403,id:1054012,msg:'Possible PHP object injection - CVE-2025-54012'"
  SecRule ARGS|REQUEST_BODY "@rx O:[0-9]+:\"[A-Za-z_\\\\]+\":[0-9]+:\{" "t:none"