CVE-2021-24884

CRITICAL
Published Oct 25, 20214y ago · Modified Jun 17, 20262w ago
9.6 CVSS 3.1
Critical
Find Similar
Published Oct 25, 2021 4y ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
9.6
Exploitability
2.8
Impact
6.0
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Changed
Confidentiality High
Integrity High
Availability High

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 2

CWE-352 Cross-Site Request Forgery (CSRF) Authentication
CWE-79 Cross-site Scripting Injection

Affected Products 1

VendorProductVersionRange
strategy11formidable_form_builder* <4.09.05

References 3

  • github.com https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf
    ExploitThird Party Advisory
  • github.com https://github.com/Strategy11/formidable-forms/pull/335/files
    PatchThird Party Advisory
  • wpscan.com https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533
    ExploitThird Party Advisory

Remediation

  • github.com https://github.com/Strategy11/formidable-forms/pull/335/files
    PatchThird Party Advisory