CVE-2026-40476
HIGHgraphql-php: Denial of Service via quadratic complexity in OverlappingFieldsCanBeMerged validation
Title source: cnaDescription
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.
References (2)
Core 2
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/webonyx/graphql-php/security/advisories/GHSA-68jq-c3rv-pcrr
X_Refsource_Misc x_refsource_misc
https://github.com/webonyx/graphql-php/releases/tag/v15.31.5
Scores
CVSS v3
7.5
EPSS
0.0049
EPSS Percentile
37.8%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-407
Status
published
Products (2)
webonyx/graphql-php
< 15.31.5 (2 CPE variants)
webonyx/graphql-php
0 - 15.31.5Packagist
Published
Apr 17, 2026
Tracked Since
Apr 18, 2026