Is CVE-2026-30241 in the CISA KEV catalog?

No. CVE-2026-30241 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-30241?

CVE-2026-30241 has a CVSS v3 base score of 8.2 (HIGH).

What is the EPSS score for CVE-2026-30241?

CVE-2026-30241 has an EPSS score of 0.36% (28th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-30241

HIGH

8.2

CVSS v3

NVD

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.

CWE-863

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Exploit Intelligence

0.36%probability of exploitation in 30 days

28thpercentile

Low risk: more likely to be exploited than 28% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-12.