Description

Unauthenticated SQL Injection in Newsletter Subscription Form – User Subscriptions Form, Capture Email <= 1.5.9 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.3",
  "pubDate": "2026-10-06T09:17:53.433Z",
  "pubdate": "2026-10-06T09:17:53.433Z",
  "executiveSummary": "An unauthenticated SQL injection vulnerability has been identified within the \"User Subscriptions Form\" of the \"Capture Email\" product in versions up to and including 1.5.9. This vulnerability represents a critical security risk as it allows remote, unauthenticated attackers to execute arbitrary SQL commands directly against the backend database.\nBy exploiting the newsletter subscription form, which is typically exposed publicly to collect user emails, an attacker can bypass traditional input validation mechanisms. The risk implications of this flaw are severe, potentially leading to unauthorized data access, modification, or deletion within the database.\nFurthermore, depending on the database management system (DBMS) configuration and underlying operating system privileges, an attacker could escalate privileges, exfiltrate sensitive user credentials, or potentially achieve remote code execution on the hosting server. Because the vulnerability resides in a public-facing newsletter subscription component, no administrative privileges or authentication credentials are required to initiate the attack. Organizations utilizing \"Capture Email\" versions 1.5.9 or earlier must take immediate action to secure their environments against active exploitation.",
  "technicalDetails": "The vulnerability exists within the input handling logic of the \"User Subscriptions Form\" provided by the \"Capture Email\" software component (versions <= 1.5.9). Specifically, the application fails to properly sanitize, filter, or parameterize user-supplied input submitted through the newsletter subscription interface before incorporating it into an active SQL query structure.\nWhen a user submits an email address to subscribe to the newsletter, the application processes this input via a backend SQL query (typically an INSERT or SELECT statement designed to check for existing subscriptions or add new records). Because the input parsing mechanism lacks parameterized queries (prepared statements) or robust input sanitization, the interpreter cannot distinguish between user-supplied data and executable SQL code. Consequently, an unauthenticated remote attacker can craft a payload containing SQL control characters and commands and inject them directly into the vulnerable field.\nThe attack flow typically proceeds through several structured phases. First, the attacker locates the publicly accessible newsletter subscription form rendered by the \"User Subscriptions Form\" of \"Capture Email\". Second, the attacker crafts a specialized SQL injection payload. Depending on the database configuration and response behavior, this payload could utilize Union-based, Error-based, Boolean-based blind, or Time-based blind SQL injection techniques. For example, a Union-based payload would attempt to append a secondary SELECT query to retrieve sensitive data from other database tables, such as administrator credentials or system configuration parameters. Third, the attacker transmits an HTTP POST or GET request containing the payload within the email input parameter directly to the application server without requiring any authentication tokens. Fourth, the application server processes the malicious request, concatenating the unsanitized input directly into the database query string. Finally, the backend database engine executes the mutated query, interpreting the injected SQL commands with the privileges of the database connection user and returning the output to the attacker.\nThe post-exploitation impact of this vulnerability is significant. An attacker can completely compromise the confidentiality, integrity, and availability of the backend database. This includes harvesting stored user emails, password hashes, and personal identifiable information (PII). In high-risk scenarios where the database service runs with elevated system-level privileges (such as sa in MS SQL or root in MySQL with FILE privileges enabled), the attacker could read or write local files, or even execute arbitrary system commands on the hosting operating system, leading to full server compromise."
}