7.5High

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.

What this means for your business

  • It affects Webonyx Graphql-Php. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 40% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Webonyx Graphql-Php, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Scoring

CVSS
7.5 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4
6.9
Weakness
CWE-407
Assigned by
security-advisories@github.com

Dates

Published
2026-04-17
Last modified
2026-09-14
Sources
NVD

Affected products

  • Webonyx Graphql-Php- 15.31.5

As listed in the NVD configuration data. Not a statement about your estate.

References