CVE-2025-48375: Schule School Management System DoS Flaw

CVE-2025-48375 Overview

CVE-2025-48375 affects Schule, an open-source school management system. Versions prior to 1.0.1 lack rate limiting controls on the forgot_password.php endpoint responsible for email-based one-time password (OTP) generation. Attackers can abuse the OTP request functionality to flood targeted users with emails. This creates denial-of-service (DoS) conditions and enables harassment through email flooding. The issue is tracked under [CWE-770: Allocation of Resources Without Limits or Throttling]. Version 1.0.1 resolves the vulnerability by introducing proper request throttling.

Critical Impact
Unauthenticated attackers can trigger unlimited OTP emails to any registered user, resulting in mailbox flooding, service disruption, and potential exhaustion of outbound email infrastructure.

Affected Products

Schule School Management System version 1.0.0
Schule School Management System versions prior to 1.0.1
Vendor: schule111

Discovery Timeline

2025-05-23 - CVE-2025-48375 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-48375

Vulnerability Analysis

The vulnerability resides in the password recovery workflow of the Schule application. The forgot_password.php endpoint accepts email addresses and generates OTP messages without enforcing any request frequency limits. An attacker can submit repeated OTP requests targeting a specific user account. Each request triggers a new email dispatch through the application's mail transport.

The absence of throttling controls allows automated scripts to issue thousands of OTP requests per minute. This behavior consumes server resources, saturates outbound mail queues, and floods the target mailbox with authentication messages. Downstream effects include SMTP provider rate limiting and possible blacklisting of the sending domain.

Root Cause

The root cause is missing input rate control on a publicly accessible endpoint. The application does not track OTP requests per email address, per source IP, or per session. It also lacks CAPTCHA or proof-of-work challenges that would deter automated abuse. This maps directly to CWE-770, where a resource-consuming operation is exposed without allocation limits.

Attack Vector

Exploitation requires only network access to the application's login area. No authentication or user interaction is needed. An attacker sends repeated HTTP POST requests to the forgot-password endpoint with a target victim's email address. Each request causes the server to generate a new OTP and dispatch an email. Attackers can script this behavior using standard HTTP tooling to sustain the flood.

The vulnerability primarily impacts availability. It does not directly expose credentials or allow account takeover, but sustained flooding can obscure legitimate password reset requests and enable social engineering follow-ups.

Detection Methods for CVE-2025-48375

Indicators of Compromise

High volume of HTTP POST requests to forgot_password.php from a single source IP or small IP range within a short time window.
Spikes in outbound SMTP traffic from the Schule application server, particularly OTP emails sent to the same recipient repeatedly.
Multiple OTP generation entries for the same user account in application logs within seconds of each other.
SMTP provider warnings, throttling notices, or reputation degradation on the sending domain.

Detection Strategies

Deploy web application firewall (WAF) rules that count requests to password reset endpoints per source IP and per target email.
Correlate application logs with mail server logs to identify disproportionate OTP dispatch patterns.
Baseline normal forgot-password traffic volumes and alert on statistical anomalies exceeding the baseline by a defined threshold.

Monitoring Recommendations

Enable verbose logging on the forgot_password.php handler capturing source IP, target email, timestamp, and User-Agent.
Forward web server and mail server logs to a centralized SIEM for correlation and long-term retention.
Configure alerts for outbound email queue depth increases and for SMTP relay errors that indicate rate limiting by upstream providers.

How to Mitigate CVE-2025-48375

Immediate Actions Required

Upgrade Schule School Management System to version 1.0.1 or later, which introduces rate limiting on OTP generation.
Restrict access to the password reset endpoint at the reverse proxy or WAF layer with per-IP request quotas until the upgrade is complete.
Review recent application and mail logs for evidence of abuse and notify affected users if flooding occurred.

Patch Information

Version 1.0.1 remediates the vulnerability by adding rate limiting controls to the OTP request functionality. Refer to the GitHub Security Advisory GHSA-h3f2-mc85-67gc for release details and upgrade instructions.

Workarounds

Configure Nginx or Apache limit_req directives to cap requests to the forgot-password URL at a low rate per client IP.
Deploy a CAPTCHA challenge in front of the password reset form to block automated request flooding.
Implement server-side cooldown logic that rejects OTP requests for the same email address within a defined interval.

bash

# Nginx rate limiting example for the forgot-password endpoint
http {
    limit_req_zone $binary_remote_addr zone=otp_limit:10m rate=5r/m;

    server {
        location = /forgot_password.php {
            limit_req zone=otp_limit burst=3 nodelay;
            limit_req_status 429;
            proxy_pass http://schule_backend;
        }
    }
}