CVE-2026-40476: graphql-go is a Go implementation of GraphQL

Q: How do I fix CVE-2026-40476?

graphql-php: upgrade to 15.31.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-40476 being exploited?

CVE-2026-40476 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-40476 affect?

CVE-2026-40476 affects graphql-php. Severity is high (CVSS 7.5). 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 th

Q: How urgent is CVE-2026-40476?

Priority 44/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2026-40476 is a high-severity flaw (CVSS 7.5) affecting graphql-php. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 v

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-407
Published	2026-04-17
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: webonyx

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-17 22:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

webonyx graphql-php UPGRADE

Affected: < 15.31.5

Fixed in: 15.31.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy graphql-php || rpm -q graphql-php || graphql-php --version

2. UPGRADE to 15.31.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade graphql-php

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade graphql-php

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40476?

graphql-php: upgrade to 15.31.5. Exact commands for each OS are on this page.

Is CVE-2026-40476 being exploited?

CVE-2026-40476 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40476 affect?

CVE-2026-40476 affects graphql-php. Severity is high (CVSS 7.5). 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 th

How urgent is CVE-2026-40476?

Priority 44/100. High severity; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

References

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