CVE-2023-0376 in Qubely Plugin
Summary
by MITRE • 01/16/2024
The Qubely WordPress plugin before 1.8.5 does not validate and escape some of its block options before outputting them back in a page/post where the block is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 06/02/2025
The Qubely WordPress plugin vulnerability CVE-2023-0376 represents a critical stored cross-site scripting weakness that affects versions prior to 1.8.5. This flaw exists within the plugin's handling of block options where insufficient input validation and output escaping mechanisms fail to properly sanitize user-provided data before rendering it back to pages or posts where the blocks are embedded. The vulnerability specifically targets the contributor role and above, making it particularly concerning as it allows users with relatively low privileges to execute malicious scripts against other users who view the affected content.
The technical implementation of this vulnerability stems from the plugin's failure to apply proper sanitization procedures to block configuration parameters. When administrators or contributors create or modify content using Qubely blocks, the plugin stores these configuration options in the WordPress database without adequate validation. During subsequent page rendering, these unsanitized values are directly outputted back to the browser without proper HTML escaping, creating an environment where malicious scripts can be executed when other users access pages containing the compromised blocks. This stored XSS vulnerability operates through the standard XSS attack vector where crafted input is persisted in the database and executed in the context of other users' browsers.
The operational impact of CVE-2023-0376 extends beyond simple script execution as it can enable attackers to perform various malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation within the WordPress environment. Since contributors and above can exploit this vulnerability, attackers can potentially compromise user sessions, modify content, or gain unauthorized access to sensitive information. The stored nature of this vulnerability means that the malicious scripts remain active until the affected content is removed or the plugin is updated, making it particularly dangerous for sites with multiple contributors or users who regularly create content. This vulnerability directly maps to CWE-79 which defines Cross-Site Scripting as a common weakness in web applications where untrusted data is not properly sanitized before being rendered in web pages.
Mitigation strategies for this vulnerability require immediate patching of the Qubely plugin to version 1.8.5 or later where the sanitization issues have been addressed. Organizations should also implement additional security measures including regular security audits of installed plugins, monitoring of user activity for suspicious content creation, and implementation of Content Security Policies to limit the impact of potential XSS attacks. The vulnerability demonstrates the critical importance of input validation and output escaping in web applications, aligning with ATT&CK technique T1566.001 which covers the use of malicious content to establish initial access through web application vulnerabilities. Administrators should also consider implementing web application firewalls and regular security scanning to detect and prevent exploitation of similar vulnerabilities in other plugins or themes that may be present in the WordPress environment.