CVE-2011-4958 in SilverStripe
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the process function in SSViewer.php in SilverStripe before 2.3.13 and 2.4.x before 2.4.6 allows remote attackers to inject arbitrary web script or HTML via the QUERY_STRING to template placeholders, as demonstrated by a request to (1) admin/reports/, (2) admin/comments/, (3) admin/, (4) admin/show/, (5) admin/assets/, and (6) admin/security/.
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Analysis
by VulDB Data Team • 05/09/2026
The CVE-2011-4958 vulnerability represents a critical cross-site scripting flaw in SilverStripe content management systems that affected versions prior to 2.3.13 and 2.4.6. This vulnerability resides within the SSViewer.php file's process function, which handles template rendering and processing of user-supplied input. The flaw specifically targets the QUERY_STRING parameter processing, allowing attackers to inject malicious scripts or HTML code directly into template placeholders. The vulnerability's exploitation occurs through administrative interfaces, making it particularly dangerous as it could enable attackers to compromise administrative sessions and potentially gain full system control. The attack surface includes multiple administrative endpoints such as admin/reports/, admin/comments/, admin/, admin/show/, admin/assets/, and admin/security/, all of which process user input without proper sanitization. This vulnerability aligns with CWE-79, which defines cross-site scripting as a weakness where untrusted data is incorporated into web pages without proper validation or escaping, and it maps to ATT&CK technique T1059.001 for command and scripting interpreter. The vulnerability demonstrates a classic input validation failure where user-supplied data from the query string is directly embedded into templates without adequate sanitization or encoding.
The technical implementation of this vulnerability exploits the way SilverStripe's template processing engine handles dynamic content insertion. When users navigate to any of the affected administrative URLs, the system processes the QUERY_STRING parameters and passes them directly to template placeholders without proper HTML escaping or sanitization. This creates an environment where attackers can craft malicious URLs containing script tags or other HTML content that gets executed in the context of authenticated admin sessions. The vulnerability's impact is amplified because it affects administrative interfaces, meaning that successful exploitation could allow attackers to view, modify, or delete content, manage users, or even execute arbitrary code on the server. The flaw essentially bypasses the application's security controls by treating user input as trusted content, which is a fundamental principle violation in secure programming practices. Attackers can leverage this vulnerability to steal session cookies, perform unauthorized actions, or redirect users to malicious sites, making it a significant threat to both data integrity and system availability.
The operational impact of CVE-2011-4958 extends beyond immediate script execution, as it represents a pathway for more sophisticated attacks including session hijacking and privilege escalation. When exploited, this vulnerability allows attackers to gain unauthorized access to administrative functions, potentially leading to complete system compromise. The vulnerability's presence in multiple administrative endpoints increases the attack surface significantly, providing attackers with several potential entry points. Organizations running affected SilverStripe versions face risks of data breaches, unauthorized content modification, and potential lateral movement within their network infrastructure. The vulnerability's exploitation requires minimal technical skill, making it particularly dangerous as it can be leveraged by attackers with limited expertise. Security teams must consider the broader implications of this vulnerability, including potential credential theft, unauthorized data access, and the possibility of establishing persistent backdoors through the compromised administrative accounts. The attack vector through QUERY_STRING parameters means that exploitation can occur through simple web browser navigation or even through phishing emails containing malicious URLs, making it a versatile threat. This vulnerability highlights the importance of input validation and output encoding in web applications, particularly in systems handling sensitive administrative functions. The security implications extend to compliance requirements, as exploitation could result in violations of data protection regulations and industry standards such as those defined by the OWASP Top Ten project.
Mitigation strategies for CVE-2011-4958 focus primarily on immediate patching and implementing defensive coding practices. Organizations should prioritize upgrading to SilverStripe versions 2.3.13 or 2.4.6, which contain the necessary fixes for this vulnerability. The patch addresses the root cause by implementing proper input sanitization and output encoding for template placeholders. Additional defensive measures include implementing web application firewalls to monitor and filter suspicious query string parameters, establishing strict input validation rules for all user-supplied data, and configuring proper output encoding for all template variables. Security teams should also implement monitoring for unusual administrative access patterns and establish incident response procedures for potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of keeping web applications updated and maintaining robust security practices including regular security assessments and code reviews. Organizations should also consider implementing content security policies to further protect against script injection attacks, and establish security training programs for developers to prevent similar vulnerabilities in custom code. The remediation process should include thorough testing of patched applications to ensure that the fix does not introduce regressions in functionality while maintaining the security enhancements.