Is CVE-2025-64166 actively exploited?

No active exploitation of CVE-2025-64166 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2025-64166 be exploited remotely?

Yes. CVE-2025-64166 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2025-64166?

CVE-2025-64166 has a CVSS score of 5.4 (MEDIUM).

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MEDIUM

CVE-2025-64166

CWE-352Published: March 5, 2026· Updated: Mar 5, 2026

5.4

CVSS v3.1

EPSS:0.01%probability of exploitation in 30 daysPercentile:0.2th

Official Description

Mercurius is a GraphQL adapter for Fastify. Prior to version 16.4.0, a cross-site request forgery (CSRF) vulnerability was identified. The issue arises from incorrect parsing of the Content-Type header in requests. Specifically, requests with Content-Type values such as application/x-www-form-urlencoded, multipart/form-data, or text/plain could be misinterpreted as application/json. This misinterpretation bypasses the preflight checks performed by the fetch() API, potentially allowing unauthorized actions to be performed on behalf of an authenticated user. This issue has been patched in version 16.4.0.

NVD Source

Technical Analysis

CVE-2025-64166 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.