webonyx graphql-php up to 15.31.4 OverlappingFieldsCanBeMerged algorithmic complexity

Summaryinfo

A vulnerability identified as problematic has been detected in webonyx graphql-php up to 15.31.4. This affects the function OverlappingFieldsCanBeMerged. The manipulation leads to algorithmic complexity. This vulnerability is uniquely identified as CVE-2026-40476. The attack is possible to be carried out remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in webonyx graphql-php up to 15.31.4. This issue affects the function OverlappingFieldsCanBeMerged. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. Using CWE to declare the problem leads to CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Impacted is availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-40476 since 04/13/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 15.31.5 eliminates this vulnerability. The upgrade is hosted for download at github.com.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Programming Language Software

Vendor

• webonyx

Name

• graphql-php

Version

• 15.31.0
• 15.31.1
• 15.31.2
• 15.31.3
• 15.31.4

Website

• Product: https://github.com/webonyx/graphql-php/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion