Description

Unauthenticated Cross Site Scripting (XSS) in WP QuickLaTeX <= 3.8.8 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-09-03T17:17:24.650Z",
  "pubdate": "2026-09-03T17:17:24.650Z",
  "executiveSummary": "The WP QuickLaTeX plugin, in versions 3.8.8 and below, is susceptible to an unauthenticated Stored Cross-Site Scripting (XSS) vulnerability. This security flaw originates from the improper sanitization and validation of user-supplied input before it is processed and rendered by the plugin.\nThe vulnerability allows remote, unauthenticated attackers to inject malicious JavaScript payloads into the WordPress environment. When viewed by a victim—specifically an administrator or a user with elevated privileges—the payload executes within the context of their session. This results in the compromise of the victim's session integrity, potentially leading to unauthorized administrative actions, data exfiltration, or the defacement of the affected website.\nGiven that the attack does not require prior authentication, the barrier to entry is low, posing a significant risk to site integrity and security. Successful exploitation grants an attacker the ability to perform actions on behalf of the victim, making this a high-severity issue for administrators utilizing the affected versions of the WP QuickLaTeX plugin.",
  "technicalDetails": "The vulnerability stems from the plugin's failure to adequately sanitize input parameters processed by the core WP QuickLaTeX functionality. Specifically, the plugin parses LaTeX code embedded in posts or pages; however, it fails to perform robust output encoding or content validation when rendering this data back to the browser.\nThe attack flow begins with an unauthenticated user identifying an input vector—such as a public-facing comment form, a guest post submission, or any interface that triggers the plugin's parsing engine. By crafting a specifically engineered LaTeX-formatted string containing malicious HTML/JavaScript tags (e.g., <script>alert(document.cookie)</script>), the attacker can inject arbitrary code into the WordPress database.\nWhen a legitimate user, such as a site administrator, navigates to a page where the malicious LaTeX code is rendered, the plugin's frontend component outputs the unsanitized script directly into the HTML document. Because the script originates from the same origin as the WordPress site, the victim's browser executes the payload automatically.\nThe lack of authentication requirements allows an attacker to conduct this attack without being logged in, bypassing standard WordPress access controls. Once executed, the malicious script operates within the security context of the victim's session. This grants the attacker potential access to session cookies, administrative tokens, or the ability to perform background HTTP requests to create new administrative accounts, modify site settings, or redirect traffic to malicious domains.\nThe root cause is identified as an insufficient implementation of input sanitization routines (likely lacking proper use of WordPress's internal APIs such as esc_html(), esc_attr(), or sanitize_text_field()) when the plugin handles shortcodes or LaTeX environments. This vulnerability affects all installations of WP QuickLaTeX version 3.8.8 and earlier. Without proper escaping, the plugin serves as a conduit for malicious scripts, rendering the platform's Content Security Policy (CSP) ineffective if not configured to strictly disallow inline scripts."
}