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CVE-2021-24884

CRITICAL 9.6 CVSS 3.1
Published
October 25, 2021
Last modified
June 17, 2026
NVD status
Modified
Reported by
contact@wpscan.com
Weakness
CWE-79, CWE-352
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Description

The Formidable Form Builder WordPress plugin before 4.09.05 allows to inject certain HTML Tags like <audio>,<video>,<img>,<a> and<button>.This could allow an unauthenticated, remote attacker to exploit a HTML-injection byinjecting a malicous link. The HTML-injection may trick authenticated users to follow the link. If the Link gets clicked, Javascript code can be executed. The vulnerability is due to insufficient sanitization of the "data-frmverify" tag for links in the web-based entry inspection page of affected systems. A successful exploitation incomibantion with CSRF could allow the attacker to perform arbitrary actions on an affected system with the privileges of the user. These actions include stealing the users account by changing their password or allowing attackers to submit their own code through an authenticated user resulting in Remote Code Execution. If an authenticated user who is able to edit Wordpress PHP Code in any kind, clicks the malicious link, PHP code can be edited.

Affected products and versions

  • Unknown Formidable Form Builder – Contact Form, Survey & Quiz Forms Plugin for WordPress — From 4.09.05 (including) to 4.09.05 (excluding)
  • strategy11 formidable_form_builder — Before 4.09.05

References

  • github.com https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf Exploit, Third Party Advisory
  • github.com https://github.com/Strategy11/formidable-forms/pull/335/files Patch, Third Party Advisory
  • wpscan.com https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533 Exploit, Third Party Advisory
  • nvd.nist.gov Official NVD record