CVE-2026-30241: Mercurius is a GraphQL adapter for Fastify

This month

HIGH 8.2REMOTEUPGRADE

CVE-2026-30241 is a high-severity flaw (CVSS 8.2) affecting mercurius. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mercurius is a GraphQL adapter for Fastify. Prior to version 16.8.0, Mercurius fails to enforce the configured queryDepth limit on GraphQL subscription queries received over WebSocket connections. The depth check is correctly applied to HTTP queries and mutations, but subscription queries are parsed and executed without invoking the depth validation. This allows a remote client to submit arbitrarily deeply nested subscription queries over WebSock

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-863
Published	2026-03-06
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: mercurius project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-06 22:16 UTCPublished CVE record published
2026-06-17 10:32 UTCUpdated Record last modified

mercurius project mercurius UPGRADE

Affected: < 16.8.0

Fixed in: 16.8.0

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls mercurius

2. UPGRADE to 16.8.0

npm install mercurius@">=16.8.0"

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-2026-30241?

mercurius: upgrade to 16.8.0. Exact commands for each OS are on this page.

Is CVE-2026-30241 being exploited?

CVE-2026-30241 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-2026-30241 affect?

CVE-2026-30241 affects mercurius. Severity is high (CVSS 8.2). Mercurius is a GraphQL adapter for Fastify. Prior to version 16.8.0, Mercurius fails to enforce the configured queryDepth limit on GraphQL subscription queries received over WebSocket connections. The depth check is correctly applied to HTT

How urgent is CVE-2026-30241?

Priority 42/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-64166 MEDIUM 5.4 UPGRADE Mercurius is a GraphQL adapter for Fastify

References

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