Mercurius's queryDepth limit bypassed for WebSocket subscriptions
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | mercurius | < 16.8.0 | 16.8.0 |
References
- CVSS 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- Weakness (CWE)
CWE-863- Platform
- npm
- Package
mercurius- Disclosed
- 06.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-m4h2-mjfm-mp55 - CC BY 4.0
Vulnerability history: mercurius
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 12.2021 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 2
- Low 1
Disclosures per year
- 2021: 1
- 2022: 0
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 2
-
Mercurius's queryDepth limit bypassed for WebSocket subscriptions this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.