CVE-2024-6536 in Zephyr Project Manager Plugin
Summary
by MITRE • 07/30/2024
The Zephyr Project Manager WordPress plugin before 3.3.99 does not sanitise and escape some of its settings, which could allow high privilege users such as editors and admins to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 03/16/2025
The vulnerability identified as CVE-2024-6536 affects the Zephyr Project Manager WordPress plugin version 3.3.99 and earlier, presenting a critical security risk through stored cross-site scripting flaws. This vulnerability specifically targets the plugin's handling of user settings where insufficient sanitisation and escaping mechanisms are implemented, creating an exploitable condition within WordPress environments. The flaw is particularly concerning because it allows users with editor or administrator privileges to inject malicious scripts that persist in the system, making it a stored XSS vulnerability rather than a reflected one. The vulnerability exists despite the presence of security measures that typically restrict HTML content, such as the unfiltered_html capability being disabled in multisite configurations.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitise user input within its settings management system. When high-privilege users modify plugin configurations, the input values are not adequately validated or escaped before being stored and subsequently rendered in the user interface. This allows malicious scripts to be embedded within legitimate plugin settings, which then execute in the context of other users who view these settings or interact with the affected pages. The vulnerability operates at the application layer, specifically within the WordPress plugin architecture, where user-supplied data flows through the application without proper security controls.
The operational impact of this vulnerability extends beyond simple script execution as it represents a privilege escalation vector within WordPress multisite environments. Attackers with editor-level permissions can leverage this flaw to compromise the entire system, potentially executing malicious code that could steal session cookies, redirect users to malicious sites, or perform actions on behalf of other users. In multisite setups where the unfiltered_html capability is restricted, the vulnerability becomes particularly dangerous as it bypasses the expected security boundaries that should protect against such attacks. The stored nature of the XSS means that the malicious scripts remain persistent and can affect multiple users over time, creating a long-term security risk.
Organizations should immediately update to version 3.3.99 or later of the Zephyr Project Manager plugin to remediate this vulnerability, as no effective workarounds exist for this specific flaw. Security teams should conduct thorough audits of all installed WordPress plugins to identify similar sanitisation issues, as this vulnerability demonstrates a common pattern where plugins fail to properly handle user input. The flaw aligns with CWE-79 which describes Cross-Site Scripting vulnerabilities, and represents a specific implementation issue where the principle of least privilege is violated through inadequate input validation. From an ATT&CK perspective, this vulnerability maps to T1548.003 which covers Abuse of Least Privilege and T1566.001 which involves Phishing with Social Engineering, as attackers could use this vulnerability to establish persistent access through malicious script injection. The vulnerability also demonstrates poor input validation practices that align with the broader security principle of defense in depth, where multiple layers of protection should be implemented to prevent such exploitation scenarios.