CVE-2026-40476
Analyzed Analyzed - Analysis Complete
Quadratic CPU Exhaustion in graphql-go OverlappingFields Validation

Publication date: 2026-04-17

Last updated on: 2026-05-21

Assigner: GitHub, Inc.

Description
graphql-go is a Go implementation of GraphQL. In versions 15.31.4 and below, the OverlappingFieldsCanBeMerged validation rule performs O(n²) pairwise comparisons of fields sharing the same response name. An attacker can send a query with thousands of repeated identical fields, causing excessive CPU usage during validation before execution begins. This is not mitigated by existing QueryDepth or QueryComplexity rules. This issue has been fixed in version 15.31.5.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-04-17
Last Modified
2026-05-21
Generated
2026-06-16
AI Q&A
2026-04-18
EPSS Evaluated
2026-06-15
NVD
CVE-2026-40476
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
webonyx graphql-php to 15.31.5 (exc)
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-407 An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Compliance Impact

The vulnerability in graphql-go allows an attacker to cause excessive CPU usage by sending queries with thousands of repeated identical fields, leading to potential denial of service during validation. However, there is no information provided about how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

Executive Summary

The vulnerability exists in graphql-go versions 15.31.4 and below, specifically in the OverlappingFieldsCanBeMerged validation rule. This rule performs O(n²) pairwise comparisons of fields that share the same response name. An attacker can exploit this by sending a query containing thousands of repeated identical fields, which causes excessive CPU usage during the validation phase before query execution.

This excessive CPU usage can degrade performance or potentially lead to denial of service conditions. The issue is not mitigated by existing QueryDepth or QueryComplexity rules and has been fixed in version 15.31.5.

Impact Analysis

This vulnerability can lead to excessive CPU consumption when processing specially crafted GraphQL queries with many repeated identical fields. This can degrade the performance of your application or service, potentially causing slowdowns or denial of service conditions during query validation.

Mitigation Strategies

To mitigate this vulnerability, upgrade graphql-go to version 15.31.5 or later, where the issue has been fixed.

Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-40476. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart