CVE-2026-3353 in Comment SPAM Wiper Plugin
Summary
by MITRE • 03/21/2026
The Comment SPAM Wiper plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'API Key' setting in all versions up to, and including, 1.2.1. This is due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
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Analysis
by VulDB Data Team • 03/21/2026
The vulnerability identified as CVE-2026-3353 affects the Comment SPAM Wiper plugin for WordPress, specifically targeting versions up to and including 1.2.1. This represents a critical security flaw that exploits stored cross-site scripting mechanisms within the plugin's administrative interface. The vulnerability manifests through the 'API Key' setting configuration field, which fails to properly sanitize user inputs and adequately escape output data before rendering. The flaw constitutes a direct violation of security best practices for input validation and output encoding, creating a persistent vector for malicious code injection that can affect multiple users within the affected WordPress environment.
The technical implementation of this vulnerability stems from inadequate sanitization processes within the plugin's codebase, particularly when handling the API Key configuration parameter. When administrators modify this setting, the input data does not undergo proper validation or sanitization procedures that would normally prevent malicious script injection attempts. The vulnerability's classification as stored XSS (CWE-079) indicates that the malicious payload is permanently stored within the application's database or configuration files, making it persistent and capable of executing against any user who accesses pages containing the compromised data. This particular weakness allows attackers to execute arbitrary JavaScript code within the context of the victim's browser, potentially leading to session hijacking, data theft, or further exploitation of the compromised system.
The operational impact of this vulnerability extends significantly within multi-site WordPress installations where the plugin is deployed, as these environments often contain multiple interconnected blogs sharing common administrative configurations. The vulnerability's requirement for authenticated administrator-level access ensures that only privileged users with sufficient permissions can exploit the flaw, but this access level provides extensive control over the entire WordPress network. The restriction to installations where unfiltered_html has been disabled creates a specific attack surface that security administrators must consider when implementing mitigation strategies, as it effectively limits the vulnerability's exploitation to environments with more restrictive content filtering policies. This targeted nature means that organizations with properly configured WordPress installations may be less susceptible to this particular attack vector.
Mitigation strategies for CVE-2026-3353 should prioritize immediate plugin updates to versions that address the input sanitization and output escaping deficiencies. System administrators must ensure that all WordPress installations are updated to the latest available versions of the Comment SPAM Wiper plugin, particularly in multi-site environments where the vulnerability poses the greatest risk. Additionally, implementing comprehensive input validation measures and output escaping mechanisms within the plugin's codebase represents a fundamental security improvement that aligns with ATT&CK framework techniques for preventing code injection vulnerabilities. Security monitoring should include regular checks for unauthorized modifications to plugin configurations, particularly within administrative interfaces where the vulnerability can be exploited. Organizations should also consider implementing additional security controls such as web application firewalls and regular security audits to detect and prevent similar vulnerabilities from being introduced through third-party plugins. The vulnerability's characteristics also highlight the importance of proper privilege management and least-privilege access controls, as limiting administrative access reduces the potential attack surface for such exploits.