CVE-2023-5291 in Blog Filter Plugin
Summary
by MITRE • 10/25/2023
The Blog Filter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'AWL-BlogFilter' shortcode in versions up to, and including, 1.5.3 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 04/10/2026
The vulnerability identified as CVE-2023-5291 affects the Blog Filter plugin for WordPress, specifically versions up to and including 1.5.3. This represents a critical security flaw that exploits the plugin's insufficient input sanitization and output escaping mechanisms within its AWL-BlogFilter shortcode functionality. The vulnerability creates a persistent cross-site scripting attack vector that can be leveraged by authenticated attackers who possess contributor-level permissions or higher, making it particularly concerning for WordPress environments where multiple user roles exist with varying permission levels.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user-supplied attributes when processing the AWL-BlogFilter shortcode. When administrators or contributors insert this shortcode into blog posts or pages, the plugin fails to adequately escape or validate the input parameters provided by users. This lack of proper input validation creates a persistent XSS vulnerability where malicious scripts can be stored within the WordPress database and executed whenever any user accesses pages containing the compromised shortcode. The vulnerability specifically targets the plugin's handling of attributes passed to the shortcode, allowing attackers to inject malicious JavaScript code that will execute in the context of other users' browsers.
The operational impact of CVE-2023-5291 extends beyond simple script execution, as it enables attackers to potentially escalate their privileges within the WordPress environment. Since the vulnerability requires only contributor-level permissions, it represents a significant risk for sites where contributors have access to the admin interface. Attackers can leverage this vulnerability to execute malicious scripts that may steal session cookies, redirect users to phishing sites, or even modify content in ways that could compromise the entire WordPress installation. The stored nature of the vulnerability means that once a malicious script is injected, it will persist and execute automatically whenever users access affected pages, making it particularly dangerous for high-traffic sites or those with numerous contributors.
From a cybersecurity perspective, this vulnerability aligns with CWE-79 which describes improper neutralization of input during web page generation, specifically addressing cross-site scripting flaws. The attack vector follows patterns consistent with ATT&CK technique T1566.001 which covers spearphishing attachments, though in this case the attack occurs through legitimate plugin functionality rather than email attachments. Organizations should immediately update to the latest version of the Blog Filter plugin to address this vulnerability, as the fix typically involves implementing proper input sanitization and output escaping mechanisms. Additionally, administrators should review user permissions and consider implementing additional security measures such as web application firewalls and regular security audits to prevent exploitation of similar vulnerabilities in other plugins or themes.