webonyx/graphql-php has quadratic validation cost in OverlappingFieldsCanBeMerged via inline fragments

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary OverlappingFieldsCanBeMerged validation rule has O(n^2 x m^2) worst case via flattened inline fragments. The CVE-2023-26144 named-fragment cache does not cover inline fragments. A 364 KB query (200 outer x 100 inner inline fragments) consumes 117 seconds of CPU per request, with no comparison budget and no validation timeout. Affected Component src/Validator/Rules/OverlappingFieldsCanBeMerged.php Description graphql-php is a PHP port of graphql-js and inherits the same OverlappingFieldsCanBeMerged algorithm. The rule performs an explicit O(n^2) pairwise comparison loop over fields collected for each response name (collectConflictsWithin), and recurses into sub-selections via findConflict. When the rule receives a query in which several inline fragments select the same response name at multiple nesting levels, the cost compounds to O(n^2 x m^2) where n and m are the number of inline fragments at the outer and inner levels respectively. graphql-php includes a…

Published by the source

4 May 2026, 22:22 UTC

Last modified by the source

4 May 2026, 22:22 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fc86-6rv6-2jpm

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# Patch Next advisory brief: GHSA-fc86-6rv6-2jpm

Advisory: webonyx/graphql-php has quadratic validation cost in OverlappingFieldsCanBeMerged via inline fragments
IDs: GHSA-fc86-6rv6-2jpm
Record: https://patchnext.com/advisories/ghsa-fc86-6rv6-2jpm (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: webonyx/graphql-php 15.32.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist webonyx/graphql-php: affected < 15.32.2; fixed in 15.32.2

## Suggested inspection (read-only)
- Packagist webonyx/graphql-php: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on webonyx/graphql-php.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-fc86-6rv6-2jpm (GitHub-reviewed advisory GHSA-fc86-6rv6-2jpm lists affected ranges: Packagist webonyx/graphql-php >=0 <15.32.2)

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