CVE-2026-30241

2.7 LOW 0.4% exploit odds Fix listed Auth & access

What it is

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 WebSocket, bypassing the intended depth restriction. On schemas with recursive types, this can lead to denial of service through exponential data resolution on each subscription event. This issue has been patched in version 16.8.0.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-03-06 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:32 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 2.7 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-03-06 22:16 UTC
Last modified: 2026-06-17 10:32 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-863 · Incorrect authorization
Record status: Analyzed

Affected

Mercurius Project Mercurius < 16.8.0

Attack profile CVSS 4.0 · 2.7

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: None
Integrity: Low
Availability: Low

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-30241.md and follow it. Check whether this project is affected by CVE-2026-30241. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record