CVE-2025-66838: Aris DoS Vulnerability via File Upload

CVE-2025-66838 Overview

A resource exhaustion vulnerability exists in Software AG ARIS version 10.0.23.0.3587512 and earlier versions. The file upload functionality does not enforce any rate limiting or throttling, allowing users to upload files at an unrestricted rate. An attacker can exploit this behavior to rapidly upload a large volume of files, potentially leading to resource exhaustion such as disk space depletion, increased server load, or degraded performance. This vulnerability is classified as CWE-770 (Allocation of Resources Without Limits or Throttling).

Critical Impact

Attackers with low privileges can cause denial of service conditions by exhausting server disk space and system resources through unrestricted file uploads.

Affected Products

• Software AG ARIS v10.0.23.0.3587512
• Software AG ARIS versions prior to v10.0.23.0.3587512

Discovery Timeline

• 2026-01-07 - CVE-2025-66838 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-66838

Vulnerability Analysis

This vulnerability stems from missing rate limiting controls in the file upload functionality of ARIS. The application fails to implement proper throttling mechanisms that would limit the number or frequency of file uploads from a single user or session. Without these protective controls, authenticated users can submit an excessive number of file upload requests in rapid succession.

The vulnerability requires network access and low-level authentication (valid user credentials), but does not require user interaction to exploit. The impact is primarily on system availability, as the attack can lead to disk space exhaustion, increased I/O load, and degraded application performance affecting all users of the system.

Root Cause

The root cause is an allocation of resources without limits or throttling (CWE-770). The ARIS file upload endpoint lacks server-side validation to enforce:

• Maximum number of uploads per time period
• Rate limiting per user session or IP address
• Upload queue management or throttling mechanisms
• Disk quota enforcement per user

This absence of resource allocation controls allows attackers to abuse the upload functionality beyond its intended use case.

Attack Vector

The attack is conducted over the network and requires low-privilege authentication to the ARIS platform. An attacker with valid credentials can:

1. Authenticate to the ARIS application
2. Identify the file upload endpoint
3. Script automated requests to rapidly upload files
4. Continue uploading until server resources are exhausted

The attack does not require any special privileges beyond basic user access to the file upload functionality. A proof-of-concept repository is available on GitHub demonstrating this exploitation technique.

Detection Methods for CVE-2025-66838

Indicators of Compromise

• Abnormal spike in file upload requests from a single user or IP address
• Rapid disk space consumption on servers hosting ARIS
• Unusual increase in HTTP POST requests to file upload endpoints
• Server performance degradation correlated with upload activity

Detection Strategies

• Monitor web server logs for high-frequency upload requests from individual sessions
• Implement alerting on disk space utilization thresholds for ARIS storage locations
• Track file upload counts per user session and flag anomalous patterns
• Review application logs for repeated file upload operations within short time windows

Monitoring Recommendations

• Configure SIEM rules to detect unusual upload patterns exceeding baseline thresholds
• Enable real-time disk space monitoring with automated alerts at 80% and 90% capacity
• Implement network traffic analysis to identify bulk upload traffic patterns
• Set up application performance monitoring to correlate slowdowns with upload activity

How to Mitigate CVE-2025-66838

Immediate Actions Required

• Implement rate limiting at the web application firewall (WAF) or reverse proxy level
• Configure disk quotas for ARIS file storage directories
• Review and restrict file upload permissions to only essential users
• Monitor disk space utilization and set up automated cleanup processes

Patch Information

No vendor patch information is currently available in the CVE data. Organizations should contact Software AG directly for guidance on security updates and patches addressing this vulnerability. Monitor the vendor's security advisories for future updates.

Workarounds

• Deploy a reverse proxy or WAF with request rate limiting for upload endpoints
• Implement application-level throttling through custom middleware if possible
• Restrict upload functionality to only necessary user roles
• Configure server-level disk quotas to prevent complete storage exhaustion
• Consider implementing upload size limits and file type restrictions as defense-in-depth measures

# Example nginx rate limiting configuration for upload endpoints
# Add to nginx server configuration

# Define rate limiting zone (10 requests per second per IP)
limit_req_zone $binary_remote_addr zone=upload_limit:10m rate=10r/s;

# Apply to upload location
location /upload {
    limit_req zone=upload_limit burst=20 nodelay;
    limit_req_status 429;
    
    # Additional protections
    client_max_body_size 50M;
    client_body_timeout 60s;
}