Horizon Alert
Summary of the vulnerability and why it matters
A critical vulnerability exists in the Formie plugin for Craft CMS, allowing unauthenticated users to submit malicious input that could lead to a severe compromise of the website. This issue arises from the plugin's handling of specially crafted values in hidden form fields, which can be evaluated as code.
- Unauthenticated users can submit malicious input.
- It could compromise the entire website.
- Confirm if Formie is used and verify exposure.
Attack Path
How an attacker could exploit the issue
An attacker can exploit this vulnerability by submitting specially crafted data to a publicly accessible web form. This data is processed by the Formie plugin, which incorrectly evaluates user-supplied values as Twig code. This could allow an attacker to execute arbitrary code or gain unauthorized access to sensitive information on the Craft CMS site.
- Entry condition: Publicly accessible web form.
- Trigger point: Submitting crafted hidden field values.
- Resulting risk: Serious site compromise.
Live Threat
Current exploitation, exposure, and threat context
Unauthenticated users could submit specially crafted values to hidden form fields that are evaluated as Twig code, potentially leading to a serious compromise of the Craft CMS site. This compromise depends on the specific template and sandbox configurations of the affected site.
- Site's template and configuration data.
- Malicious input submitted via public forms.
- Full site compromise, including data exposure.
Operational Fix
Recommended remediation, mitigation, and detection steps
Application owners and infrastructure teams are likely responsible for addressing this vulnerability in the Formie Craft CMS plugin. The first practical step is to identify all instances of the affected plugin, determine their reachability and business criticality, and then engage the accountable owners to plan remediation, which may involve coordinating with vendors and scheduling maintenance windows.
- Identify affected sites and owners.
- Verify plugin reachability and criticality.
- Plan coordinated vendor-supported updates.
