CVE-2025-70833: Smanga Authentication Bypass Vulnerability

CVE-2025-70833 Overview

An Authentication Bypass vulnerability has been identified in Smanga version 3.2.7, a self-hosted manga reader application. This critical flaw allows unauthenticated remote attackers to reset the password of any user account, including administrator accounts, leading to complete account takeover. The vulnerability exists due to insecure permission validation in the check-power.php file, which fails to properly verify user authentication before processing sensitive password reset operations.

Critical Impact

Unauthenticated attackers can fully compromise any Smanga user account, including administrators, by manipulating POST parameters to trigger unauthorized password resets without proper authentication checks.

Affected Products

• Smanga version 3.2.7
• lkw199711 Smanga (all installations running version 3.2.7)

Discovery Timeline

• 2026-02-20 - CVE-2025-70833 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2025-70833

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287) represents a fundamental failure in access control implementation within the Smanga application. The vulnerable component, check-power.php, is responsible for permission validation but contains flawed logic that allows attackers to bypass authentication entirely when performing password reset operations.

The core issue lies in the application's failure to verify that a user is properly authenticated before allowing them to execute privileged operations. When an attacker sends specially crafted POST requests to the password reset functionality, the application processes these requests without validating the requester's identity or authorization level. This enables any remote attacker, without any prior authentication, to reset passwords for arbitrary user accounts.

The attack is particularly severe because it can target administrator accounts, granting attackers full control over the Smanga instance. Once an attacker resets an administrator's password, they gain complete access to all manga libraries, user data, and system configuration settings.

Root Cause

The root cause of this vulnerability is improper implementation of permission validation in the check-power.php file. The code fails to enforce authentication requirements before processing password reset requests. Specifically, the validation logic does not verify that the requesting user is authenticated or that they have authorization to modify the target account's credentials. This represents a classic authentication bypass pattern where security-critical operations are exposed without proper access controls.

Attack Vector

This vulnerability is exploitable remotely over the network without any authentication requirements. An attacker can target any Smanga instance exposed to the network by sending malicious POST requests directly to the vulnerable endpoint. The attack flow involves:

1. The attacker identifies a Smanga instance running version 3.2.7
2. The attacker crafts POST requests targeting the password reset functionality
3. By manipulating POST parameters, the attacker specifies the target user account (including admin accounts)
4. The vulnerable check-power.php file processes the request without verifying authentication
5. The target user's password is reset to a value controlled by the attacker
6. The attacker logs in with the new credentials and gains full account access

The vulnerability requires no user interaction and can be exploited directly against any exposed Smanga installation. For additional technical details, refer to the GitHub CVE Issue Discussion.

Detection Methods for CVE-2025-70833

Indicators of Compromise

• Unexpected password reset events in application logs, particularly for administrator accounts
• Anomalous POST requests to check-power.php from external or unknown IP addresses
• Multiple failed login attempts followed by successful authentication from different IP addresses
• Unauthorized access to administrator panels or configuration changes without legitimate admin activity

Detection Strategies

• Monitor web server access logs for unusual POST request patterns targeting authentication-related endpoints
• Implement alerting on password reset activities, especially for privileged accounts
• Deploy web application firewalls (WAF) with rules to detect parameter manipulation attacks
• Enable detailed logging for all authentication and account modification operations

Monitoring Recommendations

• Configure real-time alerting for any password changes to administrator accounts
• Establish baseline patterns for normal authentication traffic and alert on deviations
• Monitor for sequential requests from the same source targeting different user accounts
• Review and audit access logs regularly for signs of reconnaissance or exploitation attempts

How to Mitigate CVE-2025-70833

Immediate Actions Required

• Restrict network access to Smanga instances to trusted networks only until a patch is available
• Implement additional authentication layers (reverse proxy with authentication) in front of the Smanga application
• Review all user accounts for unauthorized password changes and reset compromised credentials
• Enable enhanced logging and monitoring for authentication-related activities

Patch Information

At the time of publication, no official patch information is available from the vendor. Organizations should monitor the GitHub CVE Issue Discussion and the official Smanga repository for security updates. Until a patch is released, implement the workarounds and mitigations described below to reduce exposure to this vulnerability.

Workarounds

• Restrict access to Smanga to internal networks only using firewall rules or VPN requirements
• Deploy a reverse proxy with authentication (such as nginx with basic auth) to add an authentication layer
• If possible, disable or restrict access to the check-power.php endpoint at the web server level
• Consider taking the Smanga instance offline if it contains sensitive data and cannot be adequately protected

# Example nginx configuration to restrict access to Smanga
# Add authentication layer via reverse proxy

location /smanga/ {
    auth_basic "Restricted Access";
    auth_basic_user_file /etc/nginx/.htpasswd;
    proxy_pass http://localhost:8080/;
    
    # Block direct access to vulnerable endpoint
    location ~ check-power\.php$ {
        deny all;
        return 403;
    }
}