CVE-2026-1058 in Form Maker Plugin
Summary
by MITRE • 02/03/2026
The Form Maker plugin for WordPress is vulnerable to Stored Cross-Site Scripting via hidden field values in all versions up to, and including, 1.15.35. This is due to insufficient output escaping when displaying hidden field values in the admin submissions list. The plugin uses html_entity_decode() on user-supplied hidden field values without subsequent escaping before output, which converts HTML entity-encoded payloads back into executable JavaScript. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in the admin submissions view that will execute whenever an administrator accesses the submissions list.
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Analysis
by VulDB Data Team • 02/03/2026
The vulnerability identified as CVE-2026-1058 affects the Form Maker plugin for WordPress, a widely used form creation tool that allows users to build custom forms for websites. This particular flaw represents a stored cross-site scripting vulnerability that exists in all versions up to and including 1.15.35, making it a significant security concern for WordPress administrators who rely on this plugin for their website functionality. The vulnerability stems from improper handling of user-supplied data within the plugin's administrative interface, specifically in how hidden field values are processed and displayed.
The technical flaw manifests in the plugin's admin submissions list where hidden field values are processed using the html_entity_decode() function without subsequent proper escaping before output. This creates a dangerous condition where attacker-controlled input can bypass normal security measures designed to prevent malicious code execution. When an administrator views the submissions list, the previously stored malicious payloads are decoded and executed in the context of the administrator's browser session, effectively creating a persistent XSS vector. This vulnerability operates under CWE-79 which specifically addresses Cross-Site Scripting flaws and aligns with ATT&CK technique T1566.001 which covers the initial access phase through the exploitation of web application vulnerabilities.
The operational impact of this vulnerability is substantial as it allows unauthenticated attackers to inject arbitrary web scripts that will execute whenever an administrator accesses the submissions list. This creates a persistent backdoor for attackers to gain unauthorized access to administrative functions, potentially leading to complete compromise of the WordPress site. The stored nature of this vulnerability means that once an attacker successfully injects malicious code, it will continue to execute against any administrator who views the affected page, making it particularly dangerous in environments where multiple administrators access the submissions list. The vulnerability can be exploited to steal session cookies, redirect administrators to malicious sites, or execute additional attacks against the compromised system.
Mitigation strategies for this vulnerability should include immediate patching of the Form Maker plugin to version 1.15.36 or later, which addresses the output escaping issue. Administrators should also implement additional security measures such as monitoring the submissions list for unusual activity and implementing web application firewalls to detect and block malicious payloads. The principle of least privilege should be enforced by limiting access to the submissions list to only essential administrators. Security monitoring should include regular checks of the plugin's admin interfaces for signs of malicious injection, and organizations should consider implementing Content Security Policy headers to provide additional protection against XSS attacks. Additionally, regular security audits of WordPress plugins and themes should be conducted to identify and remediate similar vulnerabilities before they can be exploited by attackers.