Answer in brief
CVE-2026-40476 records a Medium severity vulnerability in graphql-php: Denial of Service via quadratic complexity in OverlappingFieldsCanBeMerged validation. The current sources do not mark it as known exploited. The current feed maps webonyx/graphql-php (composer), webonyx/graphql-php (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps webonyx/graphql-php (composer), webonyx/graphql-php (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| webonyx/graphql-phpcomposer | <=15.31.4 | 15.31.5 |
| webonyx/graphql-phpgeneric | < 15.31.5 | Not reported |
Published upstream
Apr 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.