CVE-2025-57817: Ethyca Fides Privilege Escalation Flaw

CVE-2025-57817 Overview

CVE-2025-57817 is a privilege escalation vulnerability in Fides, an open-source privacy engineering platform developed by Ethyca. The flaw exists in the OAuth client creation and update endpoints of the Fides Webserver API, which do not properly authorize scope assignment. Users holding client:create or client:update permissions can assign themselves owner-level scopes, escalating beyond their intended privilege boundary. The issue affects all versions prior to 2.69.1 and is classified under [CWE-862: Missing Authorization]. Ethyca released version 2.69.1 to address the vulnerability.

Critical Impact
Authenticated users with client:create or client:update permissions can escalate privileges to owner-level, gaining full administrative control over the Fides platform and the privacy data it governs.

Affected Products

Ethyca Fides versions prior to 2.69.1
Fides Webserver API OAuth client endpoints
Self-hosted Fides deployments using the affected releases

Discovery Timeline

2025-09-08 - CVE-2025-57817 published to NVD
2025-09-10 - Last updated in NVD database

Technical Details for CVE-2025-57817

Vulnerability Analysis

The vulnerability resides in the Fides Webserver API endpoints that handle OAuth client creation and updates. These endpoints accept scope parameters from the requester but fail to validate whether the caller is authorized to assign the requested scopes. A user already trusted with client:create or client:update permissions can therefore craft a request that grants the new or modified OAuth client owner-level scopes.

Once an attacker possesses an OAuth client with owner scopes, they hold the highest privilege tier in Fides. This permits full control over privacy configuration, data subject records, integrations, and policy enforcement. The vulnerability is exploitable over the network and does not require user interaction.

Root Cause

The root cause is missing authorization logic [CWE-862] in the OAuth client management code path. The endpoints validated that the caller possessed the permission to create or update OAuth clients but did not verify that the caller's own scopes were a superset of the scopes being assigned. This violates the principle of least privilege and enables vertical privilege escalation within the Fides authorization model.

Attack Vector

An authenticated user with client:create or client:update permissions sends a crafted request to the OAuth client endpoints, specifying owner-level scopes in the payload. The server accepts the request and issues credentials carrying the elevated scopes. The attacker then authenticates as the new client to perform owner-restricted operations.

python

# Patch excerpt: src/fides/api/oauth/utils.py
 from types import FunctionType
 from typing import Any, Callable, Dict, List, Optional, Tuple
 
-from fastapi import Depends, HTTPException, Security
+from fastapi import Depends, HTTPException, Request, Security
 from fastapi.security import SecurityScopes
 from jose import exceptions, jwe
 from jose.constants import ALGORITHMS
 from loguru import logger
 from pydantic import ValidationError
 from sqlalchemy.orm import Session
-from starlette.status import HTTP_404_NOT_FOUND
+from starlette.status import HTTP_403_FORBIDDEN, HTTP_404_NOT_FOUND
 
 from fides.api.api.deps import get_db
 from fides.api.common_exceptions import AuthenticationError, AuthorizationError

Source: GitHub Commit 2ffd125. The patch introduces HTTP_403_FORBIDDEN handling and request context to enforce scope checks against the caller's own permissions before assignment proceeds.

Detection Methods for CVE-2025-57817

Indicators of Compromise

Unexpected OAuth clients created with owner-level scopes in Fides audit logs.
Scope modifications on existing OAuth clients that expand permissions beyond the caller's role.
Authentication events from newly minted OAuth clients performing owner-restricted API calls shortly after creation.

Detection Strategies

Review Fides Webserver API logs for POST and PATCH requests to OAuth client endpoints and correlate the requested scopes with the caller's existing scope set.
Alert on any OAuth client whose assigned scopes exceed those of the user that created or last modified it.
Baseline the population of owner-scoped clients and flag deviations.

Monitoring Recommendations

Forward Fides application and access logs to a centralized analytics platform for retention and correlation.
Track privileged action sequences such as client creation followed by policy or integration changes.
Monitor for anomalous administrative activity outside expected operator accounts.

How to Mitigate CVE-2025-57817

Immediate Actions Required

Upgrade all Fides deployments to version 2.69.1 or later without delay.
Audit existing OAuth clients and revoke any that carry scopes inconsistent with their intended purpose.
Rotate credentials for OAuth clients that may have been created or modified before patching.
Restrict client:create and client:update permissions to a minimal set of trusted operators.

Patch Information

Ethyca released the fix in Fides 2.69.1. The patch adds caller scope validation in the OAuth client endpoints and returns HTTP 403 when a user attempts to assign scopes they do not themselves hold. Review the GitHub Security Advisory GHSA-hjfh-p8f5-24wr and the Fides 2.69.1 Release Notes for full details.

Workarounds

No workarounds are available per the vendor advisory; upgrading to 2.69.1 is the only remediation.
As a compensating control before patching, remove client:create and client:update permissions from all non-owner accounts.

bash

# Upgrade Fides to the patched version
pip install --upgrade 'ethyca-fides>=2.69.1'

# Verify the installed version
fides --version