CVE-2021-40910 in PHPCMS
Summary
by MITRE • 06/15/2022
There is a reflective cross-site scripting (XSS) vulnerability in the PHPCMS V9.6.3 management side.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/16/2022
The reflective cross-site scripting vulnerability identified as CVE-2021-40910 exists within the PHPCMS content management system version 9.6.3 administration interface. This flaw represents a critical security weakness that allows attackers to inject malicious scripts into web pages viewed by other users, specifically targeting the backend management area. The vulnerability stems from insufficient input validation and output sanitization mechanisms within the CMS's administrative components, creating an exploitable entry point for malicious actors seeking to compromise the system's integrity.
The technical implementation of this XSS vulnerability occurs when user-supplied input data is reflected back to the browser without proper encoding or sanitization processes. Attackers can craft malicious payloads that exploit this weakness by injecting script code through parameters or form fields within the management interface. When legitimate users with administrative privileges access these reflected pages, their browsers execute the malicious scripts within the context of the vulnerable application, potentially enabling unauthorized actions such as session hijacking, data theft, or privilege escalation. This vulnerability specifically affects the administrative side of PHPCMS, making it particularly dangerous as it targets the most privileged users of the system.
The operational impact of CVE-2021-40910 extends beyond simple script execution, as it provides attackers with opportunities to establish persistent access to the administrative interface. Successful exploitation could enable attackers to modify content, create new administrative accounts, manipulate user permissions, or even exfiltrate sensitive data from the CMS database. The reflected nature of this vulnerability means that attackers can deliver malicious payloads through various vectors including email phishing campaigns, compromised website links, or social engineering tactics that trick administrators into clicking malicious URLs. This vulnerability directly aligns with CWE-79 which categorizes cross-site scripting flaws as a primary concern in web application security, and it maps to ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
Organizations using PHPCMS V9.6.3 should immediately implement mitigations including upgrading to the latest available version that addresses this vulnerability, applying the official security patches released by the PHPCMS development team, and implementing proper input validation and output encoding mechanisms. Additional protective measures include deploying web application firewalls to detect and block malicious script payloads, restricting administrative access through network segmentation, and conducting regular security audits of the CMS components. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing robust security controls within content management systems, as these platforms often serve as primary targets for cyber attacks due to their privileged access and potential for widespread impact across web applications.