CVE-2026-110886: ChatBot Forms Deserialization Vulnerability

CVE-2026-110886 Overview

CVE-2026-110886 is a PHP Object Injection vulnerability in the QuantumCloud Conversational Forms for ChatBot WordPress plugin. The flaw stems from deserialization of untrusted data [CWE-502] and affects all versions from the initial release through 1.5.1. An unauthenticated attacker can submit crafted serialized input over the network to trigger object injection. Successful exploitation can lead to arbitrary code execution, data tampering, or full site compromise when a suitable PHP gadget chain is present.

Critical Impact
Remote, unauthenticated attackers can inject arbitrary PHP objects into vulnerable WordPress sites running Conversational Forms for ChatBot through version 1.5.1, enabling full application compromise.

Affected Products

QuantumCloud Conversational Forms for ChatBot (WordPress plugin)
All versions from initial release through 1.5.1
WordPress sites with the conversational-forms plugin installed and active

Discovery Timeline

2026-10-18 - CVE-2026-110886 published to the National Vulnerability Database (NVD)
2026-10-19 - Last updated in NVD database

Technical Details for CVE-2026-110886

Vulnerability Analysis

The vulnerability resides in how Conversational Forms for ChatBot handles untrusted input passed to PHP's unserialize() function. When user-controlled data reaches a deserialization sink without validation, PHP reconstructs arbitrary objects based on attacker-supplied class names and properties. Any class with magic methods such as __wakeup(), __destruct(), or __toString() can then be instantiated and executed in an unintended context.

In a typical WordPress environment, numerous plugins and core components contribute classes that can be chained into property-oriented programming (POP) gadgets. These gadgets convert the initial object injection into file writes, arbitrary function invocation, or remote code execution. The attacker needs no authentication, no user interaction, and only network access to the vulnerable endpoint.

Root Cause

The root cause is unsafe deserialization of untrusted data [CWE-502] within the plugin's request handling logic. The plugin accepts serialized PHP data from an attacker-reachable input vector and passes it directly to unserialize() without integrity checks, allowlisting of classes, or migration to a safe format such as JSON.

Attack Vector

Exploitation occurs over the network against the vulnerable WordPress endpoint exposed by the plugin. An attacker submits a crafted payload containing a serialized PHP object graph that references gadget classes available in the WordPress runtime. When the plugin deserializes the payload, the gadget chain executes during object construction or destruction. The impact spans confidentiality, integrity, and availability, consistent with full application compromise. See the PatchStack WordPress Vulnerability Report for additional technical context.

Detection Methods for CVE-2026-110886

Indicators of Compromise

Inbound HTTP requests to Conversational Forms for ChatBot endpoints containing serialized PHP markers such as O:, a:, or s: followed by class or property definitions.
Unexpected PHP files, webshells, or modified theme and plugin files under wp-content/.
New or modified WordPress administrator accounts and scheduled tasks (wp_cron) created shortly after suspicious plugin traffic.
Outbound connections from the web server to unfamiliar hosts following requests to the plugin.

Detection Strategies

Inspect web server and WordPress logs for POST requests to conversational-forms handlers containing serialized object patterns.
Deploy a web application firewall (WAF) rule that flags request bodies matching PHP serialization syntax targeting the vulnerable plugin paths.
Monitor PHP error logs for __wakeup, __destruct, or class-not-found errors that often accompany gadget chain probing.

Monitoring Recommendations

Alert on child processes spawned by the PHP-FPM or Apache worker, such as sh, bash, curl, or wget.
Baseline and alert on changes to WordPress core, plugin, and theme files using file integrity monitoring.
Track creation of administrative users, API keys, and application passwords in the wp_users and wp_usermeta tables.

How to Mitigate CVE-2026-110886

Immediate Actions Required

Upgrade Conversational Forms for ChatBot to a release later than 1.5.1 as soon as the vendor publishes a patched version.
Deactivate and remove the plugin from any WordPress installation where an upgrade is not immediately possible.
Audit affected sites for signs of compromise, including unknown admin users, modified files, and suspicious scheduled tasks.

Patch Information

At the time of publication, the vulnerability affects Conversational Forms for ChatBot through version 1.5.1. Review the PatchStack WordPress Vulnerability Report for the latest fixed version information from QuantumCloud.

Workarounds

Block requests to the plugin's endpoints at the WAF or reverse proxy layer until a patched version is deployed.
Restrict plugin access to authenticated administrators via server-level access controls where feasible.
Enforce least privilege on the PHP process and database user to limit the blast radius of a successful object injection.

bash

# Example WAF rule (ModSecurity) to block serialized PHP objects targeting the plugin
SecRule REQUEST_URI "@contains /conversational-forms" \
    "id:1026110886,phase:2,deny,status:403,log,\
    msg:'CVE-2026-110886 PHP Object Injection attempt',\
    chain"
    SecRule REQUEST_BODY "@rx (?:^|&|=)[Oa]:\d+:\"" "t:none"