Description

The Subscribe2 WordPress plugin before 10.46 does not properly escape a user-supplied value before reflecting it into a public subscription form, leading to Reflected Cross-Site Scripting that executes in the browser of an unauthenticated visitor who interacts with the form through a crafted link.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.1",
  "pubDate": "2026-08-07T06:16:54.553Z",
  "pubdate": "2026-08-07T06:16:54.553Z",
  "executiveSummary": "A Reflected Cross-Site Scripting (XSS) vulnerability has been identified in the Subscribe2 WordPress plugin affecting versions prior to 10.46. This security flaw stems from the failure to properly sanitize and escape a user-supplied input parameter prior to reflecting it directly into the markup of a public subscription form. The resulting vulnerability enables an unauthenticated remote attacker to craft a malicious URL containing arbitrary JavaScript payloads.\nWhen an unauthenticated visitor interacts with the specially crafted link, the injected script executes within the context of the victim's browser session. The primary risk implications include session hijacking, redirection to malicious destinations, defacement of the subscription interface, and the potential theft of sensitive user data. Successful exploitation requires user interaction, specifically tricking a visitor into clicking the malicious link, but does not demand prior authentication or elevated privileges within the WordPress environment.\nGiven the public accessibility of the subscription form, the attack surface is broadly exposed to external network traffic. Mitigation requires updating the Subscribe2 plugin to version 10.46 or later, where proper output escaping controls have been implemented to neutralize the injection vector.",
  "technicalDetails": "The vulnerability is classified as a Reflected Cross-Site Scripting (XSS) flaw localized within the public subscription form component of the Subscribe2 WordPress plugin. The root cause of the issue is inadequate input validation and the complete absence of proper context-aware output escaping for a user-supplied parameter before it is dynamically rendered in the Document Object Model (DOM).\nThe affected component is the public-facing subscription mechanism provided by the Subscribe2 plugin. Because the form is publicly accessible, the network exposure is external, allowing any unauthenticated user across the internet to initiate requests against the vulnerable endpoint. Authentication and privilege requirements are nonexistent, meaning the attacker does not need an active WordPress account or administrative privileges to successfully deliver the payload.\nThe attack flow proceeds as follows: First, the attacker crafts a malicious URL targeting the WordPress site running a vulnerable version of the Subscribe2 plugin (prior to 10.46). This URL appends an arbitrary JavaScript payload within the vulnerable, unescaped input parameter of the public subscription form. Second, the attacker distributes this crafted link to the target via phishing, social engineering, or other delivery mechanisms, enticing an unauthenticated visitor to click it. Third, the victim's browser initiates an HTTP request to the vulnerable endpoint with the malicious payload included in the query string. Fourth, the server processes the request and reflects the unsanitized user-supplied value directly into the HyperText Markup Language (HTML) response of the public subscription form without applying appropriate encoding routines such as HTML entity encoding.\nUpon receiving the HTTP response, the victim's browser parses the injected payload as legitimate executable script rather than inert text. The payload behavior executes immediately within the security context of the victim's session, possessing access to Document properties, cookies, and local storage associated with the target domain. Depending on the sophistication of the injected script, post-exploitation impact can range from session token theft and account takeover to unauthorized actions performed on behalf of the authenticated user or the harvesting of sensitive data entered into the form."
}