Cyber Resilience

CVE-2025-64166

CSRF in Mercurius Project Mercurius ≤ 16.4.0

Public PoCCSRF
Published
05 March 2026
Modified
13 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0016 6th percentile
Risk Priority 41 floored blend · peak EPSS

Summary

CVE-2025-64166 is a medium-severity CSRF (CWE-352) vulnerability in Mercurius Project Mercurius. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SC-23 (Session Authenticity) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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,…

more

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.

CWE(s)
CWE-352

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-8489Shared CWE-352
CVE-2024-51638Shared CWE-352
CVE-2025-23804Shared CWE-352
CVE-2024-36667Shared CWE-352
CVE-2024-26445Shared CWE-352
CVE-2024-22601Shared CWE-352
CVE-2023-50766Shared CWE-352
CVE-2025-9635Shared CWE-352
CVE-2025-30541Shared CWE-352
CVE-2023-27520Shared CWE-352

Affected Assets

mercurius project
mercurius
≤ 16.4.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.3.2
  • V3.5.1
  • V10.2.1

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement partial match

Access enforcement requires verifying that state-changing requests originate from the authenticated user rather than a forged cross-site source.

SC-23 Session Authenticity partial match

Protecting session authenticity prevents attackers from replaying or forging authenticated requests via the victim's browser.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require anti-CSRF controls such as tokens or SameSite attributes.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.23 Web filtering partial match
mitigates

By denying access to phishing or malicious sites, the control lowers the likelihood that a user will be tricked into submitting a forged request that performs an unintended action on another site.

A.5.7 Threat intelligence none match
none

Contextual intelligence about emerging CSRF toolkits can be translated into updated anti-CSRF token or same-site policy configurations across applications.

References