CVE-2025-13813: Mogublog Auth Bypass Vulnerability

CVE-2025-13813 Overview

A missing authorization vulnerability has been identified in moxi159753 Mogu Blog v2 up to version 5.2. This issue affects the Storage Management Endpoint at the /storage/ file path, where improper access control allows unauthorized users to potentially access or manipulate storage resources. The vulnerability can be exploited remotely, though the attack complexity is rated as high, making exploitability difficult. A public exploit is available, and the vendor was contacted about this disclosure but did not respond.

Critical Impact

Unauthorized access to storage management functions could allow attackers to read, modify, or delete stored content without proper authentication, potentially compromising blog data integrity and confidentiality.

Affected Products

• Mogu Blog v2 versions up to and including 5.2
• mogublog_project mogublog (cpe:2.3:a:mogublog_project:mogublog:*:*:*:*:*:*:*:*)

Discovery Timeline

• 2025-12-01 - CVE CVE-2025-13813 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2025-13813

Vulnerability Analysis

This vulnerability represents a classic Broken Access Control flaw (CWE-862: Missing Authorization) in the Mogu Blog application. The Storage Management Endpoint at /storage/ fails to implement proper authorization checks, allowing unauthenticated or unauthorized users to interact with storage management functionality that should be restricted to administrators or privileged users.

The attack can be initiated remotely over the network, though the complexity is considered high due to specific conditions that must be met for successful exploitation. Despite the difficulty, the public availability of exploit information increases the risk of attempted attacks against vulnerable installations.

Root Cause

The root cause of this vulnerability is the absence of authorization middleware or access control checks on the /storage/ endpoint in the Mogu Blog application. When processing requests to this endpoint, the application fails to verify whether the requesting user has the necessary permissions to perform storage management operations. This is a common oversight in web applications where developers focus on authentication (verifying identity) but neglect authorization (verifying permissions).

Attack Vector

The attack vector is network-based, requiring the attacker to send crafted HTTP requests to the vulnerable /storage/ endpoint. The exploitation flow involves:

1. Identifying a Mogu Blog v2 installation running version 5.2 or earlier
2. Sending requests directly to the /storage/ endpoint without authentication credentials or with low-privileged credentials
3. Bypassing intended access restrictions to perform unauthorized storage operations

The vulnerability allows potential read, write, or delete operations on storage resources depending on the specific endpoint functionality exposed. For detailed technical information and proof-of-concept, refer to the GitHub Access Control Report.

Detection Methods for CVE-2025-13813

Indicators of Compromise

• Unusual HTTP requests to /storage/ endpoint from unauthenticated sessions or IP addresses
• Unexpected modifications to stored files or blog content
• Access logs showing repeated requests to storage management endpoints from external sources
• File system changes in storage directories without corresponding authenticated admin actions

Detection Strategies

• Monitor web server access logs for requests to /storage/ paths from unauthenticated users
• Implement Web Application Firewall (WAF) rules to detect and alert on suspicious storage endpoint access patterns
• Deploy intrusion detection systems (IDS) configured to identify broken access control attack signatures
• Review application audit logs for storage operations performed without proper session tokens

Monitoring Recommendations

• Enable verbose logging on the Mogu Blog application to capture all storage endpoint interactions
• Set up alerts for access attempts to administrative endpoints from non-administrative user sessions
• Implement real-time monitoring of storage directory modifications with file integrity monitoring tools
• Establish baseline traffic patterns to the /storage/ endpoint to identify anomalous behavior

How to Mitigate CVE-2025-13813

Immediate Actions Required

• Restrict network access to the /storage/ endpoint using firewall rules or reverse proxy configurations
• Implement IP whitelisting for administrative endpoints if possible
• Review and audit current access control implementations across the application
• Consider taking vulnerable Mogu Blog instances offline until proper authorization can be implemented

Patch Information

No official patch is currently available from the vendor. The vendor was contacted about this vulnerability disclosure but did not respond. Users should monitor the VulDB entry and official Mogu Blog repositories for any future security updates. Until a patch is released, implementing the workarounds below is strongly recommended.

Workarounds

• Deploy a reverse proxy (nginx, Apache) with authentication requirements for the /storage/ path
• Implement custom authorization middleware at the application or web server level
• Use Web Application Firewall (WAF) rules to block unauthorized access to storage endpoints
• Consider migrating to an alternative blog platform with better security maintenance

# Example nginx configuration to restrict /storage/ access
location /storage/ {
    # Restrict access to specific IP addresses
    allow 192.168.1.0/24;
    deny all;
    
    # Alternatively, require basic authentication
    # auth_basic "Restricted Access";
    # auth_basic_user_file /etc/nginx/.htpasswd;
    
    proxy_pass http://localhost:8080;
}