CVE-2026-56005 in WP Activity Log Plugin
Summary
by MITRE • 06/25/2026
Subscriber Cross Site Scripting (XSS) in WP Activity Log <= 5.6.3.1 versions.
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Analysis
by VulDB Data Team • 06/25/2026
The vulnerability identified as subscriber cross site scripting in WP Activity Log plugin affects versions up to and including 5.6.3.1, representing a critical security flaw that allows unauthenticated attackers to inject malicious scripts into the application's user interface. This issue stems from insufficient input validation and output sanitization within the plugin's handling of user-submitted data, creating an environment where malicious payloads can be executed in the context of any authenticated user's browser session. The vulnerability specifically targets the plugin's administrative interface where logged activities are displayed, making it particularly dangerous for systems where administrators regularly monitor activity logs.
The technical implementation of this vulnerability occurs when the plugin fails to properly sanitize or escape user-controllable input parameters before rendering them within HTML output contexts. This allows an attacker to craft malicious payloads that get executed when administrators view the activity log entries containing the injected scripts. The flaw operates under CWE-79 which categorizes improper neutralization of input during web page generation, specifically targeting cross site scripting vulnerabilities where attackers can manipulate data flow between users and applications. The attack vector typically involves manipulating parameters within the plugin's administrative interface or through crafted requests that get logged and subsequently displayed to administrators.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with the ability to impersonate legitimate users, access sensitive administrative functions, steal session cookies, and potentially escalate privileges within the WordPress environment. Administrators who view compromised activity logs become victims of the XSS attack, making this particularly dangerous in environments where multiple administrators have access to the same system. The vulnerability creates a persistent threat vector where attackers can establish footholds that remain active until the malicious scripts are removed from the system or the affected plugin is updated. This makes it an ideal candidate for use in advanced persistent threat campaigns targeting WordPress installations.
Mitigation strategies for this vulnerability require immediate patching of the WP Activity Log plugin to versions that properly sanitize all input parameters and escape output content before rendering within HTML contexts. Organizations should implement comprehensive web application firewall rules to detect and block suspicious script injection patterns, while also establishing robust monitoring procedures for identifying unauthorized modifications to plugin files. The remediation process should include thorough security auditing of all installed plugins to identify similar vulnerabilities, with particular attention to those that handle user input or display external data within administrative interfaces. Additionally implementing content security policies can provide an additional layer of protection against script execution even if other defenses fail, aligning with defensive measures recommended in the mitre ATT&CK framework for web application security controls and specifically targeting T1059.007 which covers scripts executed through web applications.