CVE-2023-0143 in Send PDF for Contact Form 7 Plugin
Summary
by MITRE • 02/06/2023
The Send PDF for Contact Form 7 WordPress plugin before 0.9.9.2 does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks which could be used against high privilege users such as admins.
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Analysis
by VulDB Data Team • 03/25/2025
The vulnerability identified as CVE-2023-0143 affects the Send PDF for Contact Form 7 WordPress plugin, specifically versions prior to 0.9.9.2, presenting a critical security risk through stored cross-site scripting vulnerabilities. This issue arises from inadequate input validation and output escaping mechanisms within the plugin's shortcode attribute handling, creating a pathway for malicious actors to inject persistent malicious scripts into web pages viewed by other users.
The technical flaw stems from the plugin's failure to properly sanitize and escape shortcode attributes before rendering them back into HTML output. When contributors or users with lower privileges create or modify contact form entries, the plugin processes these inputs without sufficient validation measures. This vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, where improper validation of user-supplied data allows attackers to inject malicious scripts that execute in the context of other users' browsers. The weakness exists at the point of output rendering rather than input processing, making it a stored XSS vulnerability where malicious code persists in the application's database and executes each time the affected page is loaded.
The operational impact of this vulnerability is particularly concerning given that it can be exploited by users with minimal privileges such as contributors, who typically have limited access rights within WordPress environments. An attacker with contributor-level access could craft malicious shortcode attributes containing JavaScript payloads that would execute when administrators or other high-privilege users view the affected pages. This creates a significant risk for privilege escalation attacks, as the malicious scripts could potentially access administrative functions, steal session cookies, or redirect users to malicious websites. The vulnerability represents a serious threat to WordPress site security, especially in environments where multiple users with varying permission levels have access to form creation capabilities.
Mitigation strategies should focus on immediate plugin updates to version 0.9.9.2 or later, which contains the necessary patches to address the input validation and output escaping deficiencies. Administrators should also implement additional security measures such as restricting contributor-level access to contact form editing capabilities where possible, implementing content security policies to limit script execution, and monitoring for suspicious form submissions. The vulnerability aligns with ATT&CK technique T1566 which covers social engineering through malicious content, and T1071 which involves application layer protocols. Organizations should also consider implementing web application firewalls to detect and prevent exploitation attempts, while conducting regular security audits of WordPress plugins to ensure all components are properly maintained and patched according to security best practices.