External risk intelligence

Unauthenticated PHP Object Injection in Contact Form 7 HubSpot Integration

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-49763

A critical PHP Object Injection vulnerability exists in the Integration for Contact Form 7 HubSpot plugin. Unauthenticated attackers can exploit this flaw to potentially execute arbitrary code, compromise system data, and impact website integrity. It is important to determine if this plugin is in use and exposed on pub

4Halo Surface Signal

Deserialization

External exposure likelihood

Halo Surface Signal score for CVE-2026-49763

The vulnerability exists in a WordPress plugin designed for contact form integration. Such plugins are routinely deployed on public-facing websites to handle user input, making the vulnerable code directly reachable via the internet as part of the standard web application surface.

PCI scan relevance

PCI Relevance for CVE-2026-49763

Yes

CVE-2026-49763 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

This vulnerability is relevant to PCI scans because it allows unauthenticated PHP object injection, which can lead to remote code execution.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Horizon Alert

Summary of the vulnerability and why it matters

A critical security flaw has been identified in a widely used integration for contact forms that connects to HubSpot. This vulnerability, specifically a PHP Object Injection, could allow unauthenticated attackers to compromise systems by manipulating how data is processed. The primary concern is confirming if this technology is in use and therefore exposed.

  • Flaw allows unauthenticated attackers to inject malicious code.
  • Important for public-facing websites using contact forms.
  • Confirm relevance and assess potential exposure.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can exploit this vulnerability by sending a crafted request to a WordPress site. This request targets the Integration for Contact Form 7 HubSpot plugin, which is exposed to the network and does not require user interaction or prior authentication. If successful, the attacker can trigger a PHP Object Injection, potentially leading to the compromise of the website's data and overall integrity.

  • No authentication needed to access.
  • Triggered via a network-exposed plugin.
  • Risk of data compromise and site integrity.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in the Integration for Contact Form 7 HubSpot plugin could allow an unauthenticated attacker to inject malicious PHP objects. When the plugin processes certain data, it may be susceptible to this injection, potentially leading to the execution of arbitrary code or data manipulation on the affected system.

  • System data and service behavior.
  • Unauthenticated network access.
  • Arbitrary code execution or data compromise.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This unauthenticated PHP Object Injection vulnerability in the Integration for Contact Form 7 HubSpot plugin likely impacts public-facing websites. Application owners and platform teams should prioritize identifying instances of this plugin, assessing their reachability and business criticality, and confirming ownership before planning remediation.

  • Application owners should own this issue.
  • Verify plugin reachability and business impact.
  • Plan remediation with vendor coordination.

Frequently asked questions

What is the Integration for Contact Form 7 HubSpot plugin?

This software is a WordPress plugin that bridges contact forms on a website with HubSpot's marketing and CRM services. It is typically installed by site administrators to automate data collection, allowing incoming inquiries from web visitors to be automatically synced and processed directly into a HubSpot account for tracking and management.

What does PHP Object Injection mean in CVE-2026-49763?

This is a vulnerability class identified as CWE-502. It occurs when a program deserializes untrusted user input without sufficient validation. In the context of this CVE, an attacker sends specially crafted data that the application treats as a valid object. This allows the attacker to manipulate the program's logic or internal data structures, potentially leading to unauthorized execution of code or significant system compromise.

How is this vulnerability triggered by an attacker?

The vulnerability is triggered when an attacker sends a malicious request directly to the vulnerable plugin over the network. Because the plugin processes these requests without requiring the sender to log in or prove their identity, no prior access or user interaction is necessary to initiate the attack. Requests that do not contain the specific malicious payload structure will not trigger the flaw.

Is my website at risk if it uses this plugin?

According to Halo Surface Signal, this vulnerability is highly relevant because the plugin is designed to handle user input on public-facing websites. Because these contact forms are intended to be accessible to anyone on the internet, the vulnerable component is often directly reachable, making it easier for an attacker to reach the flawed code without needing to bypass internal network barriers.

What should I do if I run this plugin?

The first step is to verify if your WordPress installation includes the affected version of the Integration for Contact Form 7 HubSpot plugin. Once confirmed, assess the plugin's reachability and determine if it is critical to your site's functionality. Coordinate with your team to monitor for official vendor updates or guidance, as patching the software is the primary way to remove this risk.

References

Sources and related resources

Primary sources: NVD, CVE.org.

NVDPublished