CVE-2023-22477: Mercurius is vulnerable to denial of service (DoS) when using subscriptions

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-01-09 · updated 2026-06-17
Weakness: CWE-248

Description

Mercurius is a GraphQL adapter for Fastify. Any users of Mercurius until version 10.5.0 are subjected to a denial of service attack by sending a malformed packet over WebSocket to `/graphql`. This issue was patched in #940. As a workaround, users can disable subscriptions.

Affected products

mercurius-js mercurius: before 8.13.2; from 9.0.0 before 11.5.0 — fixed in 11.5.0, 8.13.2

How to fix

Upgrade to a fixed version: mercurius-js mercurius 11.5.0, 8.13.2. Check the vendor advisory for mitigations.

References

https://github.com/mercurius-js/mercurius/issues/939
https://github.com/mercurius-js/mercurius/pull/940
https://github.com/mercurius-js/mercurius/security/advisories/GHSA-cm8h-q92v-xcfc
https://github.com/mercurius-js/mercurius/issues/939
https://github.com/mercurius-js/mercurius/pull/940
https://github.com/mercurius-js/mercurius/security/advisories/GHSA-cm8h-q92v-xcfc

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