CVE-2018-7747 in Caldera Forms Plugin
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the Caldera Forms plugin before 1.6.0-rc.1 for WordPress allow remote attackers to inject arbitrary web script or HTML via vectors involving (1) a greeting message, (2) the email transaction log, or (3) an imported form.
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Analysis
by VulDB Data Team • 08/16/2025
The CVE-2018-7747 vulnerability represents a critical cross-site scripting flaw affecting the Caldera Forms WordPress plugin, which was widely used for creating contact forms and data collection tools. This vulnerability existed in versions prior to 1.6.0-rc.1 and exposed websites to remote code execution risks through malicious script injection attacks. The flaw specifically targeted three distinct input vectors within the plugin's functionality, making it particularly dangerous as attackers could exploit any of these pathways to compromise user sessions and potentially gain unauthorized access to sensitive data. The vulnerability falls under CWE-79 which categorizes cross-site scripting flaws as one of the most prevalent web application security issues, with implications extending far beyond simple script injection to include session hijacking and data theft.
The technical implementation of this vulnerability stemmed from inadequate input sanitization within the Caldera Forms plugin's handling of user-supplied data. Attackers could craft malicious payloads that would be stored and subsequently executed when legitimate users viewed the affected pages. The greeting message vector allowed attackers to inject scripts directly into form confirmation messages, while the email transaction log vulnerability enabled malicious code insertion into email records that were later displayed to administrators. The imported form vector presented another attack surface where maliciously crafted form configurations could be imported and executed without proper validation. These attack vectors directly align with ATT&CK technique T1566 which covers social engineering through malicious file or script execution, demonstrating how the vulnerability could be exploited through user interaction with seemingly legitimate content.
The operational impact of CVE-2018-7747 was significant for WordPress administrators and website owners who relied on Caldera Forms for their data collection needs. When exploited, the vulnerability could allow attackers to steal user session cookies, redirect victims to malicious websites, or execute arbitrary commands on affected systems. The attack surface was particularly concerning because it affected administrative interfaces where users would view transaction logs and form configurations, creating opportunities for privilege escalation attacks. Organizations running vulnerable versions faced potential data breaches, as the injected scripts could capture form submissions, harvest user credentials, or establish backdoor access points. The vulnerability's persistence meant that once exploited, the malicious code would continue to execute whenever affected pages were accessed, potentially compromising multiple users over extended periods.
Mitigation strategies for CVE-2018-7747 centered on immediate plugin updates to version 1.6.0-rc.1 or later, which included comprehensive input sanitization and output encoding fixes. System administrators should have implemented proper security monitoring to detect unusual activity in form submission logs and email transaction records. The vulnerability highlighted the importance of input validation and output encoding practices, principles that align with OWASP Top 10 category A03: Injection, which specifically addresses the need for proper data sanitization. Additional protective measures included implementing content security policies to limit script execution, conducting regular security audits of installed plugins, and establishing secure coding practices for WordPress development. Organizations should have also considered network-level protections such as web application firewalls to detect and block malicious script injection attempts, particularly targeting the specific input vectors mentioned in the vulnerability description. The incident underscored the critical importance of maintaining up-to-date security patches for all WordPress plugins and themes, as outdated components often represent the primary attack vectors for sophisticated cyber threats.