CVE-2025-49071: NasaTheme Flozen RCE Vulnerability

CVE-2025-49071 Overview

CVE-2025-49071 is a critical unrestricted file upload vulnerability affecting the NasaTheme Flozen WordPress theme. This vulnerability allows unauthenticated attackers to upload arbitrary files with dangerous types, including web shells, directly to the web server. Successful exploitation enables complete server compromise, providing attackers with remote code execution capabilities and full control over the affected WordPress installation.

Critical Impact

This vulnerability allows unauthenticated attackers to upload web shells and achieve remote code execution on vulnerable WordPress sites running the Flozen theme, potentially leading to complete site takeover, data exfiltration, and use of the server for further attacks.

Affected Products

• NasaTheme Flozen WordPress Theme (versions through 1.5.1)
• WordPress installations using the vulnerable Flozen theme
• Web servers hosting affected WordPress sites

Discovery Timeline

• June 17, 2025 - CVE-2025-49071 published to NVD
• June 17, 2025 - Last updated in NVD database

Technical Details for CVE-2025-49071

Vulnerability Analysis

This vulnerability falls under CWE-434 (Unrestricted Upload of File with Dangerous Type), a class of vulnerabilities where an application fails to properly validate or restrict file types during upload operations. The Flozen WordPress theme contains an arbitrary file upload flaw that does not implement adequate validation on uploaded file content, extensions, or MIME types.

The vulnerability is particularly severe because it requires no authentication to exploit. An attacker can interact with the vulnerable upload functionality without needing any WordPress user credentials. The scope is changed (as indicated in the vulnerability metrics), meaning successful exploitation impacts resources beyond the vulnerable component itself—potentially compromising the entire web server and any other applications hosted on it.

Root Cause

The root cause of this vulnerability lies in insufficient file upload validation within the Flozen theme. The theme's upload handling mechanism fails to:

1. Properly validate file extensions against a secure allowlist
2. Verify actual file content matches the declared file type
3. Implement server-side MIME type validation
4. Restrict upload directories with appropriate permissions
5. Require authentication before processing file uploads

This combination of missing security controls allows attackers to bypass any client-side restrictions and upload malicious PHP files or other executable content directly to the web server.

Attack Vector

The attack vector is network-based, requiring no user interaction and no privileges to exploit. An attacker would typically follow this attack pattern:

1. Identify a WordPress site running the vulnerable Flozen theme
2. Locate the vulnerable file upload endpoint within the theme
3. Craft a malicious request containing a web shell (typically a PHP file)
4. Upload the web shell through the vulnerable endpoint, bypassing file type restrictions
5. Access the uploaded web shell via its URL on the compromised server
6. Execute arbitrary commands on the server with the privileges of the web server process

The web shell provides persistent backdoor access, allowing attackers to execute system commands, read/write files, access databases, pivot to other systems, and maintain long-term control over the compromised server.

Detection Methods for CVE-2025-49071

Indicators of Compromise

• Unexpected PHP files or scripts appearing in WordPress upload directories or theme folders
• Web server access logs showing requests to suspicious files with parameters like cmd=, exec=, or shell=
• Unusual outbound network connections from the web server to unknown IP addresses
• Modified file timestamps on WordPress core files, themes, or plugins
• New or unauthorized user accounts created in WordPress admin panel

Detection Strategies

• Implement file integrity monitoring on WordPress installations to detect unauthorized file changes
• Monitor web server logs for POST requests to unusual endpoints within the Flozen theme directory
• Deploy web application firewall (WAF) rules to block common web shell patterns and signatures
• Use YARA rules to scan for known web shell signatures in web-accessible directories
• Enable WordPress security plugins that scan for malicious file uploads and code injections

Monitoring Recommendations

• Configure real-time alerting for new PHP file creation in WordPress wp-content directories
• Monitor web server process activity for suspicious child processes or command execution
• Implement network traffic analysis to detect command-and-control communications
• Review WordPress audit logs for unauthorized administrative actions or configuration changes

How to Mitigate CVE-2025-49071

Immediate Actions Required

• Immediately audit WordPress installations to identify sites using the NasaTheme Flozen theme
• Scan affected servers for existing web shells or indicators of compromise before patching
• Temporarily disable or remove the Flozen theme until a patched version is available and verified
• Implement WAF rules to block file upload requests to the vulnerable theme endpoints
• Review server access logs for evidence of exploitation attempts or successful compromises

Patch Information

Organizations should monitor the Patchstack WordPress Vulnerability Database for updates on patched versions of the Flozen theme. Contact NasaTheme for official security advisories and update the theme to the latest version once a patch is released. Verify the integrity of the patched version before deployment.

Workarounds

• Remove or deactivate the Flozen theme and switch to a secure alternative WordPress theme
• Implement strict file upload restrictions at the web server level using .htaccess or server configuration
• Configure the web server to prevent PHP execution in upload directories using php_flag engine off
• Deploy a web application firewall with rules specifically blocking web shell upload attempts
• Implement network segmentation to limit the impact of potential server compromise

# Configuration example - Prevent PHP execution in WordPress uploads directory
# Add to .htaccess in wp-content/uploads/

<Files *.php>
deny from all
</Files>

# Alternative using Apache configuration
<Directory "/var/www/html/wp-content/uploads">
    php_flag engine off
    <FilesMatch "\.ph(p[3457]?|t|tml)$">
        Require all denied
    </FilesMatch>
</Directory>