CVE-2026-27161 Overview
CVE-2026-27161 is a significant information disclosure vulnerability affecting all versions of GetSimple CMS, a lightweight content management system. The vulnerability arises from the CMS's reliance on .htaccess files to protect sensitive directories such as /data/ and /backups/. When Apache's AllowOverride directive is disabled—a common configuration in hardened or shared hosting environments—these access controls are silently ignored, enabling unauthenticated attackers to enumerate and download sensitive files.
Critical Impact
Unauthenticated attackers can access sensitive files including authorization.xml, which contains cryptographic salts and API keys, potentially leading to complete system compromise.
Affected Products
- GetSimple CMS (Community Edition) - All versions
- getsimple-ce getsimple_cms
Discovery Timeline
- 2026-02-21 - CVE-2026-27161 published to NVD
- 2026-02-24 - Last updated in NVD database
Technical Details for CVE-2026-27161
Vulnerability Analysis
This vulnerability represents a classic case of security misconfiguration combined with insecure default behavior (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor). GetSimple CMS relies exclusively on Apache .htaccess files to restrict access to sensitive directories containing configuration data, user credentials, and backup files.
The fundamental issue lies in the architecture's assumption that .htaccess protections will always be honored. In production environments where Apache's AllowOverride directive is set to None—a security hardening practice recommended by many hosting providers and security frameworks—the .htaccess rules are completely ignored without any warning or fallback mechanism.
When these protections fail, attackers gain network-based access to sensitive directories without requiring any authentication or user interaction. The attack complexity is low, requiring only basic HTTP requests to enumerate and retrieve files from unprotected directories.
Root Cause
The root cause is the exclusive reliance on .htaccess files for access control without implementing application-level security checks or server configuration validation. GetSimple CMS does not verify whether .htaccess protections are actually in effect, nor does it provide alternative access control mechanisms at the PHP application layer. This architectural decision creates a silent failure mode where security controls can be completely bypassed without any indication to administrators.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker can directly request files from sensitive directories such as /data/ and /backups/ via HTTP. When AllowOverride is disabled on the target server, these requests succeed, allowing the attacker to:
- Enumerate directory contents through directory listing
- Download configuration files containing sensitive data
- Access authorization.xml which stores cryptographic salts and API keys
- Retrieve backup files that may contain historical credentials or site data
The attacker can exploit this vulnerability by simply navigating to URLs such as https://target-site.com/data/ or directly requesting known sensitive files like https://target-site.com/data/other/authorization.xml.
Detection Methods for CVE-2026-27161
Indicators of Compromise
- HTTP access logs showing direct requests to /data/, /backups/, or other protected directories
- Requests for sensitive files such as authorization.xml, users.xml, or backup archives
- Unusual access patterns from external IP addresses targeting CMS data directories
- Directory listing requests (indicated by requests ending with / to protected paths)
Detection Strategies
- Monitor web server access logs for requests to /data/, /backups/, and other sensitive GetSimple CMS directories
- Implement web application firewall (WAF) rules to block direct access attempts to sensitive file paths
- Configure intrusion detection systems to alert on access to files matching patterns like *.xml in CMS data directories
- Deploy file integrity monitoring on sensitive directories to detect unauthorized access or modifications
Monitoring Recommendations
- Enable detailed access logging on the web server with client IP, requested URI, and response codes
- Set up real-time alerting for successful (HTTP 200) responses to requests targeting sensitive directories
- Periodically audit Apache configuration to ensure AllowOverride settings align with security requirements
- Monitor for credential reuse or unauthorized API access that may indicate stolen keys from authorization.xml
How to Mitigate CVE-2026-27161
Immediate Actions Required
- Verify Apache configuration to ensure AllowOverride All is enabled for the GetSimple CMS directory, or implement equivalent <Directory> restrictions directly in the main Apache configuration
- If AllowOverride cannot be enabled, manually add directory restrictions to the Apache virtual host configuration
- Review access logs for evidence of prior exploitation and rotate any potentially exposed API keys or credentials
- Consider temporarily restricting access to the entire CMS installation until proper access controls are verified
Patch Information
At the time of publication, no official patch is available for this vulnerability. The security advisory has been published by the GetSimple CMS Community Edition maintainers. Administrators should consult the GitHub Security Advisory for updates on potential fixes.
Workarounds
- Configure Apache virtual host to include explicit <Directory> directives that deny access to /data/ and /backups/ directories, which takes effect regardless of AllowOverride settings
- Move sensitive directories outside the web root entirely and update application configuration accordingly
- Implement a reverse proxy or WAF layer that blocks access to sensitive paths before requests reach the origin server
- For Nginx or other web servers, ensure equivalent access restrictions are configured since .htaccess files are Apache-specific
# Apache Virtual Host Configuration Workaround
# Add to your Apache virtual host configuration file
<Directory "/var/www/html/getsimple/data">
Require all denied
</Directory>
<Directory "/var/www/html/getsimple/backups">
Require all denied
</Directory>
# Alternatively, use FilesMatch for sensitive XML files
<FilesMatch "^(authorization|users|website)\.xml$">
Require all denied
</FilesMatch>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
