CVE-2025-32031: Apollo Gateway DOS Vulnerability

CVE-2025-32031 Overview

A denial of service vulnerability exists in Apollo Gateway, a utility for combining multiple GraphQL microservices into a single GraphQL endpoint. Prior to version 2.10.1, the query planner contained a flaw that allowed queries with deeply nested and reused named fragments to bypass internal optimizations, resulting in prohibitively expensive query planning operations. Because the query planner does not enforce a timeout, a small number of malicious queries can exhaust system resources and render the gateway completely inoperable.

Critical Impact

Attackers can craft GraphQL queries with deeply nested named fragments to exhaust server resources, causing complete denial of service for the Apollo Gateway endpoint and all dependent microservices.

Affected Products

• Apollo Gateway versions prior to 2.10.1
• @apollo/gateway package for Node.js

Discovery Timeline

• 2025-04-07 - CVE-2025-32031 published to NVD
• 2025-08-01 - Last updated in NVD database

Technical Details for CVE-2025-32031

Vulnerability Analysis

This vulnerability falls under the category of Algorithmic Complexity Attack and Resource Exhaustion (CWE-770: Allocation of Resources Without Limits or Throttling). The Apollo Gateway query planner includes an optimization designed to significantly speed up planning for applicable GraphQL selections. However, this optimization can be systematically bypassed through carefully constructed queries.

When a GraphQL query contains deeply nested and reused named fragments, the query planner generates numerous selections where the standard optimization does not apply. This forces the planner to process these selections through slower, unoptimized code paths. The cumulative effect of processing many such selections leads to exponentially longer planning times.

The critical flaw lies in the absence of any timeout mechanism in the query planner. This design oversight means that even a small number of maliciously crafted queries can monopolize CPU resources, blocking legitimate requests and eventually causing the gateway to become completely unresponsive.

Root Cause

The root cause of this vulnerability is twofold: first, the query planner's optimization logic does not adequately handle edge cases involving deeply nested named fragments that reference each other repeatedly. Second, there is no resource limiting or timeout enforcement in the query planning phase, allowing computationally expensive operations to run indefinitely.

This combination creates a scenario where attackers can predictably trigger worst-case algorithmic complexity in the query planner, turning it into an effective denial of service vector. The vulnerability represents a classic example of resource exhaustion through algorithmic complexity exploitation.

Attack Vector

The attack can be executed remotely over the network by any unauthenticated user who can submit GraphQL queries to the affected Apollo Gateway endpoint. An attacker crafts a GraphQL query that contains multiple levels of deeply nested named fragments, where these fragments reference each other in a pattern that maximizes selection generation while minimizing optimization applicability.

The malicious query is submitted to the GraphQL endpoint like any normal query. The query planner begins processing and generates a large number of selections that bypass the optimization. Without a timeout, the planner continues processing indefinitely, consuming CPU resources. Additional malicious queries compound the effect, eventually exhausting available resources and causing service denial for all users.

Detection Methods for CVE-2025-32031

Indicators of Compromise

• Unusually high CPU utilization on servers running Apollo Gateway
• GraphQL query logs showing requests with deeply nested named fragments
• Timeout errors or unresponsive behavior from the gateway endpoint
• Increased memory consumption correlating with specific query patterns

Detection Strategies

• Monitor query planning duration metrics and alert on anomalous spikes
• Implement query complexity analysis to flag queries with excessive fragment nesting depth
• Review GraphQL query logs for patterns of deeply nested named fragments
• Set up application performance monitoring (APM) to detect resource exhaustion

Monitoring Recommendations

• Configure alerts for CPU utilization exceeding normal thresholds on gateway servers
• Implement query depth and complexity limiting at the application layer
• Monitor request queue depth and response latency for early warning signs
• Track the ratio of query planning time to execution time as an anomaly indicator

How to Mitigate CVE-2025-32031

Immediate Actions Required

• Upgrade @apollo/gateway to version 2.10.1 or later immediately
• Review and implement GraphQL query complexity limits as a defense-in-depth measure
• Consider implementing rate limiting on the GraphQL endpoint
• Monitor system resources closely until the patch is applied

Patch Information

Apollo has remediated this vulnerability in @apollo/gateway version 2.10.1. The fix addresses the optimization bypass issue and prevents the exponential planning time caused by deeply nested named fragments. Organizations should upgrade to this version as soon as possible.

For detailed information about the fix, refer to the GitHub Pull Request #3236, the Security Advisory GHSA-p2q6-pwh5-m6jr, and the Release Notes for version 2.10.1.

Workarounds

• Implement query depth limiting to restrict maximum nesting levels for fragments
• Deploy a Web Application Firewall (WAF) with GraphQL-aware rules to block suspicious query patterns
• Use query cost analysis plugins to reject queries exceeding computational thresholds
• Consider temporarily restricting access to the GraphQL endpoint to trusted clients until patching is complete

# Upgrade @apollo/gateway to the patched version
npm install @apollo/gateway@2.10.1