CVE-2026-78257: Booking and Rental Manager PHP Injection

CVE-2026-78257 Overview

CVE-2026-78257 is a PHP Object Injection vulnerability in the Booking and Rental Manager for WooCommerce WordPress plugin, affecting versions up to and including 2.7.5. The flaw allows an authenticated user with Contributor-level privileges to inject serialized PHP objects, which the plugin deserializes without validation. Successful exploitation can trigger PHP object injection chains that lead to code execution, file manipulation, or data compromise depending on available gadget chains. The vulnerability is categorized under CWE-502: Deserialization of Untrusted Data.

Critical Impact
Authenticated attackers with Contributor access can trigger PHP object injection, potentially leading to arbitrary code execution and full site compromise on affected WordPress installations.

Affected Products

Booking and Rental Manager for WooCommerce plugin, versions <= 2.7.5
WordPress sites running the vulnerable plugin with Contributor or higher user registration enabled
WooCommerce-based booking and rental deployments using this plugin

Discovery Timeline

2026-08-27 - CVE-2026-78257 published to NVD
2026-08-27 - Last updated in NVD database

Technical Details for CVE-2026-78257

Vulnerability Analysis

The vulnerability resides in the Booking and Rental Manager for WooCommerce plugin, where user-supplied input reaches a PHP unserialize() call without sufficient validation. Contributors, who normally have limited posting privileges, can submit crafted serialized payloads that the plugin deserializes during routine processing. When PHP deserializes attacker-controlled data, it instantiates arbitrary classes and invokes magic methods such as __wakeup() or __destruct(). Attackers chain these method invocations across classes present in WordPress core, WooCommerce, or other installed plugins to reach dangerous sinks. The resulting execution can modify site content, read sensitive files, or achieve remote code execution when a suitable gadget chain exists.

Root Cause

The root cause is unsafe deserialization of untrusted input [CWE-502]. The plugin passes attacker-controlled data to unserialize() without cryptographic verification or type restrictions. PHP object injection issues escalate in severity based on classes loaded in the runtime, making WordPress environments with many plugins particularly exposed.

Attack Vector

Exploitation requires network access and authenticated Contributor privileges. The attacker submits a crafted payload through a plugin input path that flows to the vulnerable deserialization sink. No user interaction is required beyond the attacker's own authenticated request. Refer to the Patchstack Vulnerability Advisory for advisory-level technical detail.

Detection Methods for CVE-2026-78257

Indicators of Compromise

Requests from Contributor accounts containing serialized PHP markers such as O: or a: followed by class names in POST bodies or query strings
Unexpected creation of PHP files, cron jobs, or admin users following Contributor activity
WordPress error logs showing unserialize() warnings or __wakeup/__destruct execution errors originating from plugin paths

Detection Strategies

Inspect web server and application logs for serialized object patterns submitted by low-privilege accounts
Monitor WordPress audit logs for privilege changes, new administrator accounts, or plugin/theme modifications after Contributor logins
Deploy a Web Application Firewall (WAF) rule that flags serialized PHP objects in requests to plugin endpoints

Monitoring Recommendations

Alert on file writes to wp-content/plugins/, wp-content/uploads/, and PHP files across the web root
Track newly registered Contributor accounts and correlate their request activity with sensitive plugin URLs
Ingest WordPress and WooCommerce logs into a centralized SIEM for cross-source correlation and retention

How to Mitigate CVE-2026-78257

Immediate Actions Required

Update the Booking and Rental Manager for WooCommerce plugin to a version above 2.7.5 once the vendor publishes a fix
Audit all Contributor accounts and remove or suspend accounts that are unused or unverified
Disable open user registration for the Contributor role until the plugin is patched

Patch Information

Refer to the Patchstack Vulnerability Advisory for the latest patched version guidance. Apply vendor updates through the WordPress plugin update mechanism and verify the installed version after upgrading.

Workarounds

Deactivate the Booking and Rental Manager for WooCommerce plugin until a patched release is available
Enforce WAF rules that block serialized PHP payloads in Contributor-scoped endpoints
Restrict access to the WordPress admin area with IP allowlisting or multi-factor authentication for all non-Subscriber accounts

bash

# Example WAF rule concept: block serialized PHP objects in POST bodies
# ModSecurity-style pseudo-rule
SecRule REQUEST_BODY "@rx (?:^|&)[^=]+=(?:O|a):\d+:\{" \
    "id:1026078257,phase:2,deny,log,msg:'Possible PHP object injection payload (CVE-2026-78257)'"