CVE-2026-30241

Description

## Description 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. ## Workarounds Disable subscriptions and, in general, queries over the WebSocket.

How to fix CVE-2026-30241

To remediate CVE-2026-30241, upgrade the affected package to a fixed version below.

• —upgrade to 16.8.0 or later

Is CVE-2026-30241 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, < 16.8.0

CVSS scores

References (4)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-30241
• PATCHgithub.com/mercurius-js/mercurius
• WEBgithub.com/mercurius-js/mercurius/commit/5b56f60f4b0d60780b0ff499a479bd830bdd6986
• WEBgithub.com/mercurius-js/mercurius/security/advisories/GHSA-m4h2-mjfm-mp55