CVE-2022-1889 in Newsletter Plugin
Summary
by MITRE • 06/20/2022
The Newsletter WordPress plugin before 7.4.6 does not escape and sanitise the preheader_text setting, which could allow high privilege users to perform Stored Cross-Site Scripting attacks when the unfilteredhtml is disallowed
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Analysis
by VulDB Data Team • 06/20/2022
The vulnerability identified as CVE-2022-1889 affects the Newsletter WordPress plugin version 7.4.5 and earlier, representing a critical stored cross-site scripting flaw that enables authenticated attackers with high privilege levels to execute malicious scripts within the context of other users' browsers. This issue specifically targets the preheader_text setting parameter, which fails to properly escape and sanitize user input before rendering it in the web interface. The vulnerability arises from insufficient input validation and output escaping mechanisms within the plugin's administrative components, creating an avenue for persistent malicious code injection that can affect multiple users simultaneously.
The technical exploitation of this vulnerability occurs when high-privilege users, such as administrators or editors with sufficient permissions, manipulate the preheader_text setting through the WordPress admin interface. When the plugin processes this unvalidated input, it fails to apply appropriate HTML escaping or sanitization routines, allowing malicious script code to be stored within the plugin's configuration. Upon subsequent page loads or administrative interactions, this stored script executes in the browsers of other users who access the affected interface, particularly those with lower privileges or regular user accounts. The vulnerability is particularly concerning because it operates within the context of the WordPress administrative environment where users have elevated permissions, potentially enabling attackers to escalate their privileges or access sensitive data.
The operational impact of CVE-2022-1889 extends beyond simple script execution, as it can facilitate various advanced attack vectors including credential theft, session hijacking, and privilege escalation within the WordPress environment. Attackers could potentially inject malicious scripts that harvest user credentials, redirect traffic to malicious domains, or establish backdoors for persistent access. The vulnerability's persistence stems from its stored nature, meaning that once exploited, the malicious code remains active until manually removed from the plugin's configuration settings. This makes the attack particularly dangerous in multi-user environments where administrators regularly interact with the plugin interface, as the malicious payload continues executing for all users who access the affected administrative pages.
Security professionals should note that this vulnerability aligns with CWE-79, which describes Cross-Site Scripting flaws resulting from insufficient output escaping or sanitization of user-controllable data. The flaw also corresponds to ATT&CK technique T1059.001, which covers command and scripting interpreter usage, as attackers can leverage stored XSS to execute malicious scripts within user browsers. The vulnerability's classification as a stored XSS issue means that the malicious payload is permanently stored on the server and executed every time the affected page is loaded, making it more severe than reflected XSS attacks that require user interaction with specific malicious links. Organizations should prioritize immediate patching to version 7.4.6 or later, while also implementing additional monitoring for suspicious administrative activities and user account behavior that might indicate exploitation attempts.