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knilkantha/Security Advisory: Stored XSS via Malicious PDF Upload (Fixed in v3.0.9)

Last active May 5, 2025 07:28
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Security Advisory: Stored XSS via Malicious PDF Upload (Fixed in v3.0.9)
@knilkantha

knilkantha commented May 5, 2025 •
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Security Advisory: Stored XSS via Malicious PDF Upload (Fixed in v3.0.9)

Date Published: Jan 24, 2025
Plugin: Everest Forms
Vulnerability Type: Stored Cross-Site Scripting (XSS)
Date Reported: Jan 16, 2025
Affected Versions: Up to 3.0.8
Patched Version: 3.0.9
Status: Fixed
Reporter: Mohammed Kamal (0xM0K74)

Summary

A security vulnerability was reported in Everest Forms that could allow malicious PDF uploads to trigger a stored XSS attack when viewed from the WordPress admin panel. This issue was responsibly disclosed to our team, and we have resolved it in version 3.0.9, released on Jan 24, 2025.

Details

The vulnerability affected the file upload field within forms created using Everest Forms. A malicious actor could upload a specially crafted PDF containing embedded JavaScript. If an admin or privileged user viewed the form submission or accessed the file via the admin dashboard, the script could execute in their browser.

Potential impact:

  • Execution of unauthorized scripts in the admin context
  • Session hijacking, unauthorized actions, or sensitive data exposure

What We’ve Done

We took immediate steps to investigate, verify, and resolve the issue:

  • Improved validation and sanitization of uploaded files
  • Added stricter content-type and file integrity checks
  • Escaped and sanitized output in admin views related to uploaded files

Fixed In: ✅ Everest Forms version 3.0.9

Recommendations for Users

  • Update Everest Forms to version 3.0.9 or higher

    We strongly urge all users to update to the latest version to ensure their sites remain secure.

Acknowledgment

We thank Mohammed Kamal (0xM0K74) for reporting this issue responsibly and helping us keep our plugin secure for everyone.

Final Note

The security and privacy of our users remain our top priority. We continuously monitor and improve our codebase to maintain a safe plugin environment. If you encounter any potential security issues, please contact us directly at https://everestforms.net/support/

Thank you for trusting Everest Forms.

—
Everest Forms Team

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