CVE-2018-10109 in Monstra
Summary
by MITRE
Monstra CMS 3.0.4 has a stored XSS vulnerability when an attacker has access to the editor role, and enters the payload in the content section of a new page in the blog catalog.
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Analysis
by VulDB Data Team • 07/21/2025
The vulnerability identified as CVE-2018-10109 represents a critical stored cross-site scripting flaw within Monstra CMS version 3.0.4 that specifically targets users with editor privileges. This weakness allows authenticated attackers to inject malicious scripts into the content management system that persist in the database and execute whenever the compromised content is rendered to other users. The vulnerability manifests within the blog catalog's content section where editors can create new pages, making it particularly dangerous as it leverages the trust relationship between legitimate users and the CMS interface. The stored nature of this vulnerability means that the malicious payload remains embedded in the system even after the initial attack vector is closed, potentially affecting multiple users who view the compromised content.
The technical flaw stems from insufficient input validation and output sanitization within the CMS's content handling mechanisms. When editors enter content into the blog catalog, the system fails to properly escape or filter special characters that could be interpreted as HTML or JavaScript code. This lack of proper sanitization creates an environment where attackers can inject malicious scripts that execute in the context of other users' browsers. The vulnerability specifically affects the content section of new pages, indicating that the sanitization process is bypassed during the page creation workflow. According to CWE classification, this represents a CWE-79: Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security. The attack vector requires an attacker to already possess an editor role, but this privilege escalation path can be achieved through various means including credential theft, social engineering, or exploitation of other vulnerabilities in the system.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data theft, and redirection to malicious websites. Once an attacker successfully injects a payload, they can steal user cookies, which would allow them to impersonate legitimate users and potentially gain administrative privileges. The persistent nature of stored XSS means that the attack can continue to affect users long after the initial compromise, making it particularly dangerous for content management systems where editors regularly update content. This vulnerability directly maps to several ATT&CK techniques including T1059.007 for scripting and T1531 for credential access, as attackers can leverage the compromised system to extract sensitive information and maintain persistence. The impact is particularly severe in environments where multiple editors have access to the system, as the attack surface expands exponentially with each privileged user.
Mitigation strategies for CVE-2018-10109 should focus on immediate patching of the Monstra CMS to version 3.0.5 or later, which contains the necessary security fixes. Organizations should also implement robust input validation at multiple layers including client-side and server-side sanitization, with particular attention to the content handling mechanisms in the blog catalog. The principle of least privilege should be enforced by limiting editor permissions to only necessary functions and implementing role-based access controls that minimize the potential impact of compromised accounts. Additional defensive measures include implementing content security policies to prevent execution of unauthorized scripts, regular security auditing of user inputs, and monitoring for suspicious content submissions. Organizations should also consider implementing web application firewalls to detect and block known XSS attack patterns, and establish incident response procedures for rapid detection and remediation of similar vulnerabilities. The vulnerability highlights the critical importance of proper input sanitization and output encoding in web applications, aligning with OWASP Top 10 recommendations for preventing cross-site scripting attacks through proper validation and encoding of user-supplied data.