Low 2.7Published Mar 6, 2026

CVE-2026-30241Mercurius: queryDepth limit bypassed for WebSocket subscriptions

Updated under an hour ago (Oct 26, 2026, 10:10 AM ET)

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It affects mercurius-js mercurius and 1 other product. Add what you run to find out whether that includes you.

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Every CVE for mercurius-js mercurius

Exploited in the last 30 days

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.

CVSS: 2.7 LOW (v4.0, CNA)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
Weakness (CWE): CWE-863
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Mar 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

mercurius-js mercurius mercurius_js:mercurius (from the name)	before 16.8.0	CNA record
mercurius_project mercurius mercurius_project:mercurius	before 16.8.0	NVD

References

https://github.com/mercurius-js/mercurius/security/advisories/GHSA-m4h2-mjfm-mp55x-refsource-confirm, vendor-advisory
https://github.com/mercurius-js/mercurius/commit/5b56f60f4b0d60780b0ff499a479bd830bdd6986x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.