CVE-2023-5971 in Save as PDF Plugin
Summary
by MITRE • 05/14/2024
The Save as PDF Plugin by Pdfcrowd WordPress plugin before 3.2.0 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
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Analysis
by VulDB Data Team • 01/10/2026
The CVE-2023-5971 vulnerability affects the Save as PDF Plugin by Pdfcrowd WordPress plugin version 3.2.0 and earlier, representing a critical stored cross-site scripting flaw that undermines web application security. This vulnerability specifically targets the plugin's handling of user settings, where insufficient sanitization and escaping mechanisms leave the system exposed to malicious input. The flaw is particularly concerning because it allows high-privilege users such as administrators to execute malicious scripts within the context of other users' browsers, even when WordPress security measures like the unfiltered_html capability are properly restricted.
The technical implementation of this vulnerability stems from the plugin's failure to properly validate and sanitize user-supplied data before storing it in the WordPress database. When administrators configure plugin settings through the WordPress admin interface, the input values are not adequately escaped or filtered before persistence. This creates a stored XSS vector where malicious JavaScript code can be injected into the plugin's configuration parameters and subsequently executed whenever the affected settings are rendered in the admin interface or processed by the plugin's functionality. The vulnerability's exploitation becomes possible even in environments where unfiltered_html is disabled, such as multisite WordPress installations where security restrictions are typically more stringent.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers with administrator privileges to potentially escalate their access within the WordPress environment. The stored nature of the XSS means that malicious scripts can persist indefinitely until manually removed, allowing attackers to perform actions such as stealing user sessions, modifying content, redirecting users to malicious sites, or even exfiltrating sensitive data from the WordPress administration area. In a multisite setup, this vulnerability becomes particularly dangerous as it could compromise multiple sites within the network, potentially allowing attackers to gain access to sensitive administrative functions across the entire WordPress multisite installation.
This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in software applications, and demonstrates how improper input validation and output escaping can create persistent security weaknesses. From an ATT&CK framework perspective, this vulnerability maps to T1059.001 for command and scripting interpreter and T1566.001 for phishing with malicious attachments, as attackers could use the stored XSS to redirect users to malicious content or harvest credentials. The exploitation of this vulnerability requires administrative privileges, placing it in the category of privilege escalation attacks that leverage application-level flaws rather than network-level vulnerabilities.
Mitigation strategies for CVE-2023-5971 focus primarily on immediate plugin updates to version 3.2.0 or later, where the sanitization and escaping mechanisms have been properly implemented. Organizations should also conduct thorough security audits of their WordPress installations to identify any other plugins or themes that might exhibit similar sanitization issues. Regular monitoring of plugin updates and maintaining an updated security baseline through proper access controls and privilege management helps prevent exploitation of such vulnerabilities. Additionally, implementing web application firewalls and content security policies can provide additional layers of protection against potential XSS attacks that might attempt to exploit this or similar vulnerabilities.