How severe is CVE-2026-30241?

CVE-2026-30241 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2026-30241 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-30241?

CVE-2026-30241 affects Mercurius Project Mercurius. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-30241?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-30241 have an EU (EUVD) identifier?

Yes. CVE-2026-30241 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10081.

When was CVE-2026-30241 published?

CVE-2026-30241 was published on 2026-03-06 and last updated on 2026-06-17.

CVE-2026-30241

CVE-2026-30241 is a high-severity vulnerability in Mercurius Project Mercurius with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: High (CVSS 3.x base score 8.2)
CVSS v4: 2.7
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10081
Weakness: CWE-863
Affected product: Mercurius Project Mercurius
Published: 2026-03-06
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-30241?: 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.
How severe is CVE-2026-30241?: CVE-2026-30241 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2026-30241 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-30241?: CVE-2026-30241 affects Mercurius Project Mercurius. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-30241?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-30241 have an EU (EUVD) identifier?: Yes. CVE-2026-30241 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10081.
When was CVE-2026-30241 published?: CVE-2026-30241 was published on 2026-03-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mercurius_project:mercurius:*:*:*:*:*:node.js:*:*

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