Vulnerability in Webonyx Graphql-Php
CVE-2026-40476
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.
EPSS: 0.005 (39.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Webonyx Graphql-php — versions < 15.31.5
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-40476?
- CVE-2026-40476 is a high-severity vulnerability in Webonyx Graphql-Php, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-04-17.
- How severe is CVE-2026-40476?
- High severity. CVSS v3 base score is 7.5 out of 10.