CVE‑2026‑89435：Formidable Forms ≤6.35 版可被授權使用者任意安裝外掛
CVE-2026-89435 - Formidable Forms <= 6.35 - Authenticated (Subscriber+) Arbitrary Plugin Installation via 'file_url' Parameter
Formidable Forms 6.35 版及以前因 file_url 引數缺乏 URL 字首驗證，授權使用者（訂閱者級別）可安裝任意外掛。
此漏洞需網站為免費版（未安裝 Formidable Pro）才能利用。
此漏洞允許擁有訂閱者許可權的使用者安裝任意外掛，凸顯 WordPress 外掛安全治理的重要性。
The Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More plugin for WordPress is vulnerable to Arbitrary Plugin Installation in all versions up to, and including, 6.35 via the 'file_url' parameter parameter. This is due to insufficient URL prefix validation in validate_url_is_in_s3_bucket() and a permission callback that relies solely on a shared token obtainable by any user with the delegable frm_view_forms capability, without checking install_plugins or activate_plugins capabilities. This makes it possible for authenticated attackers, with subscriber-level access and above, to install arbitrary plugins on the server. Exploitation additionally requires that the site is free-only (Formidable Pro is NOT installed).
Impact
Affected Products
The following products are affected by CVE-2026-89435
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Update Formidable Forms to version 6.36 or later to fix arbitrary plugin installation.
- Update Formidable Forms plugin to version 6.36 or later.
- Restrict access to the frm_view_forms capability.
- Ensure install_plugins and activate_plugins capabilities are properly checked.
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-89435.
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89435 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89435
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-89435 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89435 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
十月. 30, 2026
Action Type Old Value New Value Added Description The Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More plugin for WordPress is vulnerable to Arbitrary Plugin Installation in all versions up to, and including, 6.35 via the 'file_url' parameter parameter. This is due to insufficient URL prefix validation in validate_url_is_in_s3_bucket() and a permission callback that relies solely on a shared token obtainable by any user with the delegable frm_view_forms capability, without checking install_plugins or activate_plugins capabilities. This makes it possible for authenticated attackers, with subscriber-level access and above, to install arbitrary plugins on the server. Exploitation additionally requires that the site is free-only (Formidable Pro is NOT installed). Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-74 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89435.json">CVE-2026-89435</a> Added Reference https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1459 Added Reference https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1489 Added Reference https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1514 Added Reference https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAppController.php#L1167 Added Reference https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/helpers/FrmAppHelper.php#L4934 Added Reference https://plugins.trac.wordpress.org/changeset/3746820/formidable/trunk/classes/controllers/FrmAddonsController.php Added Reference https://plugins.trac.wordpress.org/changeset?reponame=&new=3750372%40formidable%2Ftags%2F7.0&old=3688662%40formidable%2Ftags%2F6.35 Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/87661de6-e835-495e-9bd2-4d64b4718108?source=cve
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.