Executive Intelligence Brief

A critical vulnerability, CVE-2026-78657, has been identified in the SigmaForms Pro – AI Generated Forms plugin for WordPress. This vulnerability has a CVSS score of 9.8, indicating a high severity level. The vulnerability allows unauthenticated attackers to delete arbitrary files on the server, which can lead to remote code execution. The affected plugin has a significant deployment footprint across WordPress installations. Immediate patching or mitigation is recommended.

Threat Overview

The SigmaForms Pro – AI Generated Forms plugin for WordPress is a popular tool used to generate forms on WordPress sites. The plugin is vulnerable to arbitrary file deletion due to insufficient file path validation in the delete_submission_files function. This vulnerability affects all versions up to and including 1.4.11 of the plugin.

The vulnerability is particularly concerning because it allows unauthenticated attackers to delete arbitrary files on the server. This can easily lead to remote code execution when a critical file, such as wp-config.php, is deleted. The malicious path traversal URL is submitted via a form upload field and stored in the database, with deletion triggered when an administrator deletes the submission record from the admin panel.

Technical Deep Dive

Vulnerability Classification

The vulnerability is classified as CWE-22, which refers to Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'). This class of vulnerability occurs when a web application does not properly validate user input, allowing an attacker to traverse the file system and access or delete files outside of the intended directory.

The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, which indicates that the vulnerability has a high impact on confidentiality, integrity, and availability.

Root Cause Analysis

The root cause of this vulnerability is the insufficient file path validation in the delete_submission_files function. The function does not properly check the file path, allowing an attacker to submit a malicious path traversal URL via a form upload field.

Attack Vector & Chain

The attack vector for this vulnerability involves submitting a malicious path traversal URL via a form upload field. The URL is stored in the database, and deletion is triggered when an administrator deletes the submission record from the admin panel.

The attack chain involves the following steps:

  • Initial access: The attacker submits a malicious path traversal URL via a form upload field.
  • Weaponization: The attacker prepares a malicious URL that traverses the file system and targets a critical file, such as wp-config.php.
  • Delivery & Exploitation: The malicious URL is stored in the database, and deletion is triggered when an administrator deletes the submission record from the admin panel.
  • Post-Exploitation: The attacker gains access to the server and can execute arbitrary code.

Exploitation Scenario Walkthrough

Scenario: Arbitrary File Deletion via Malicious Path Traversal URL

Reconnaissance: The attacker discovers a WordPress site using the SigmaForms Pro – AI Generated Forms plugin.

Weaponization: The attacker prepares a malicious path traversal URL that targets a critical file, such as wp-config.php.

Delivery & Exploitation: The attacker submits the malicious URL via a form upload field, and it is stored in the database. When an administrator deletes the submission record from the admin panel, the malicious URL is triggered, deleting the targeted file.

Post-Exploitation: The attacker gains access to the server and can execute arbitrary code, potentially leading to remote code execution.

Impact Realization: The attacker achieves remote code execution, potentially leading to a complete compromise of the server.

Exploitation in the Wild

The vulnerability is not currently being actively exploited in the wild. However, given its high severity and potential for remote code execution, it is likely that attackers will target this vulnerability in the future.

Impact Analysis

Direct Impact

The direct impact of this vulnerability is the potential for arbitrary file deletion, which can lead to remote code execution. An attacker can delete critical files, such as wp-config.php, potentially leading to a complete compromise of the server.

Downstream & Cascading Effects

The downstream and cascading effects of this vulnerability include:

  • Supply chain risk: If the vulnerable plugin is used in a supply chain, an attacker could potentially compromise the entire supply chain.
  • Regulatory implications: A breach resulting from this vulnerability could lead to regulatory issues, such as GDPR or HIPAA violations.
  • Customer data exposure: If the vulnerable plugin is used to process customer data, an attacker could potentially access or delete sensitive customer information.

Affected Products & Versions

The vulnerability affects all versions up to and including 1.4.11 of the SigmaForms Pro – AI Generated Forms plugin for WordPress.

Detection & Threat Hunting

Indicators of Compromise

Indicators of compromise for this vulnerability include:

  • Unusual file deletion activity on the server.
  • Suspicious form submissions or uploads.
  • Anomalous database activity.

Detection Rules & Signatures

Detection rules and signatures for this vulnerability include:

  • Monitoring for unusual file deletion activity.
  • Detecting suspicious form submissions or uploads.
  • Identifying anomalous database activity.

Threat Hunting Queries

Threat hunting queries for this vulnerability include:

  • Searching for suspicious form submissions or uploads.
  • Identifying unusual file deletion activity.
  • Monitoring for anomalous database activity.

Remediation & Hardening

Immediate Actions (0-24 hours)

Immediate actions to remediate this vulnerability include:

  • Patching the vulnerable plugin to version 1.4.12 or later.
  • Monitoring for suspicious activity.

Short-Term Hardening (1-7 days)

Short-term hardening measures include:

  • Implementing additional security controls, such as web application firewalls (WAFs) or intrusion detection systems (IDS).
  • Enhancing monitoring and logging.

Strategic Recommendations

Strategic recommendations for preventing this vulnerability class include:

  • Regularly updating and patching plugins and software.
  • Implementing secure coding practices.
  • Conducting regular security audits and penetration testing.

Analyst Assessment

The analyst assesses that this vulnerability has a high likelihood of being exploited in the future due to its high severity and potential for remote code execution. Organizations should prioritize patching or mitigating this vulnerability immediately.

Sources

  • National Vulnerability Database (NVD)
  • Wordfence