Overview

This report discusses the critical vulnerability CVE-2025-57816 that affects the Fides open-source privacy engineering platform. The vulnerability is related to the ineffective IP-based rate limiting in the Fides Webserver API, which potentially allows attackers to bypass the rate limits and cause denial of service. This vulnerability is significant due to its potential for causing system compromise or data leakage.

Vulnerability Summary

CVE ID: CVE-2025-57816
Severity: High (CVSS: 7.5)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Fides | Prior to version 2.69.1

How the Exploit Works

The vulnerability lies in the Fides Webserver API’s built-in IP-based rate limiting feature. This feature, designed to protect the system from being overwhelmed by too many requests, is ineffective in environments with CDNs, proxies or load balancers. The system incorrectly applies rate limits based on directly connected infrastructure IPs rather than client IPs, and stores counters in-memory rather than in a shared store. This allows attackers to bypass intended rate limits and potentially cause denial of service.

Conceptual Example Code

An attacker could potentially exploit this vulnerability by sending numerous requests from different IPs or by using a proxy to change their IP after each request. Here is a conceptual example of how the vulnerability might be exploited using an HTTP request:

POST /api/request HTTP/1.1
Host: target.example.com
X-Forwarded-For: attacker_proxy_ip
Content-Type: application/json
{ "request_data": "..." }

In this example, the attacker sends a POST request to the target server’s API, with the X-Forwarded-For header set to an IP address of their choosing. By changing this IP address for each request, the attacker can bypass the rate limiting and potentially overwhelm the server, leading to a denial of service.

Mitigation Guidance

Users are advised to apply the vendor patch (version 2.69.1) which fixes the issue. If the patch cannot be applied immediately, users may implement rate limiting externally at the infrastructure level using a Web Application Firewall (WAF), an Intrusion Detection System (IDS) or similar technology as a temporary mitigation method. This vulnerability only affects deployments that rely on Fides’s built-in rate limiting for protection. Deployments using external rate limiting solutions are not affected.