CVE-2025-60083: 
WordPress vulnerability analysis and mitigation

CVE-2025-60083 is a Deserialization of Untrusted Data vulnerability (Object Injection) in the PDF Invoice Builder for WooCommerce WordPress plugin developed by add-ons.org. It affects all versions from n/a through 6.5.0 (NVD) / through 6.3.2 (ENISA/Patchstack). The vulnerability was published on December 18, 2025, and assigned by Patchstack. It carries a CVSS v3.1 base score of 8.8 (High) (Feedly, Patchstack).

The root cause is improper deserialization of untrusted user-supplied data within the plugin, classified as CWE-502 (Deserialization of Untrusted Data), enabling PHP Object Injection (CAPEC-586). An authenticated attacker with low-privilege access (e.g., a subscriber or customer account) can supply a crafted serialized PHP object via a network request, which the plugin deserializes without adequate validation. If a suitable PHP gadget chain exists in the WordPress environment, this can be leveraged to achieve arbitrary code execution, file manipulation, or other malicious outcomes. No specific technical write-up or public PoC code has been identified at this time (Feedly, Patchstack).

Successful exploitation can result in full compromise of confidentiality, integrity, and availability of the affected WordPress site. A low-privileged attacker could execute arbitrary code on the server, access sensitive data (including customer invoices and payment information stored by WooCommerce), modify or delete site content, and potentially pivot to other systems on the same hosting environment. The vulnerability requires no user interaction and is exploitable remotely over the network (Feedly).

1. Reconnaissance: Identify WordPress sites running the PDF Invoice Builder for WooCommerce plugin (versions ≤ 6.5.0) using tools like WPScan, Shodan, or by inspecting plugin directories (/wp-content/plugins/pdf-for-woocommerce/).
2. Obtain low-privilege access: Register or use an existing low-privilege account (e.g., WooCommerce customer) on the target site.
3. Identify the vulnerable input: Locate the plugin functionality that accepts and deserializes user-supplied data (e.g., a parameter in an invoice-related request).
4. Craft a malicious serialized payload: Using a PHP gadget chain tool (e.g., PHPGGC), generate a serialized PHP object payload targeting a gadget chain available in the WordPress/WooCommerce environment to achieve the desired effect (e.g., remote code execution, file write).
5. Submit the payload: Send the crafted serialized object to the vulnerable endpoint via an authenticated HTTP request.
6. Trigger deserialization: The plugin deserializes the object, invoking the gadget chain and executing the attacker's intended code or action on the server (Feedly).

• Network: Unusual authenticated POST requests to PDF Invoice Builder plugin endpoints containing serialized PHP data (e.g., strings beginning with O:, a:, or s: in request bodies or parameters).
• Logs: WordPress/web server access logs showing repeated requests to plugin-specific endpoints from low-privilege user accounts; PHP error logs referencing unexpected class instantiation or __wakeup/__destruct method calls.
• File System: Unexpected new PHP files or web shells in the WordPress installation directory; modifications to existing plugin or theme files with unusual timestamps.
• Process: Unusual child processes spawned by the web server process (e.g., bash, curl, wget) indicating potential code execution following deserialization.

The primary remediation is to update the PDF Invoice Builder for WooCommerce plugin to a version beyond 6.3.2 (per Patchstack) or beyond 6.5.0 (per NVD). Site administrators should also restrict plugin access to trusted users, implement a Web Application Firewall (WAF) rule to detect and block serialized PHP object payloads in requests, and audit the WordPress environment for signs of compromise. Limiting the number of registered user accounts and enforcing strong authentication (e.g., MFA) reduces the attack surface given the low-privilege requirement (Feedly, Patchstack).