CVE-2026-103542 in Form Tools
Summary
by MITRE • 10/01/2026
A flaw has been found in formtools.org Form Tools up to 3.1.1. Impacted is the function smart_fill of the file /global/code/actions.php of the component AJAX Endpoint. This manipulation of the argument url causes server-side request forgery. The attack can be initiated remotely. The exploit has been published and may be used. The project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in Form Tools, specifically affecting versions up to 3.1.1, represents a critical server-side request forgery flaw located within the AJAX endpoint component. This security defect is rooted in the smart_fill function found in the /global/code/actions.php file. The core technical issue arises from improper validation of user-supplied input passed via the url argument. When an attacker provides a maliciously crafted URL, the application fails to adequately restrict or validate this input before processing it. Consequently, the server executes HTTP requests on behalf of the victim system, directing these requests toward arbitrary destinations determined by the attacker rather than intended internal resources. This behavior is characteristic of Server-Side Request Forgery, commonly categorized under CWE-918 in industry standard classification systems for software weaknesses.
The operational impact of this vulnerability allows a remote attacker to initiate interactions with backend services that are otherwise inaccessible from the external network. By leveraging SSRF, an adversary can probe internal network infrastructure, access sensitive data stored on local servers, or interact with cloud metadata endpoints such as those found in AWS EC2 instances to retrieve temporary security credentials. This capability significantly expands the attack surface beyond the immediate application layer, potentially leading to full system compromise if combined with other vulnerabilities within the internal environment. The fact that an exploit has been published and is available for use indicates a high risk of active exploitation in the wild, particularly against organizations running unpatched instances of Form Tools 3.1.1 or earlier versions without adequate network segmentation or web application firewall protections.
Mitigation strategies must focus on immediate remediation through software updates as well as defensive architectural controls. The primary and most effective solution is to upgrade Form Tools to a version that has addressed this specific flaw in the smart_fill function, ensuring that input validation mechanisms are robustly implemented for all URL parameters. In cases where an immediate patch is not feasible, administrators should implement strict allow-listing of permitted URLs or domains within the application configuration to prevent arbitrary external requests. Additionally, deploying network-level controls such as firewalls can help restrict outbound connections from the server hosting Form Tools to only necessary and trusted endpoints. Monitoring logs for unusual outbound traffic patterns originating from the web server can also aid in early detection of exploitation attempts while longer-term security hardening measures are applied.